Merge patch series "fs: fat: Handle 'FAT sector size mismatch'"

Varadarajan Narayanan <varadarajan.narayanan@oss.qualcomm.com> says:

The disk_read() and disk_write() functions of the FAT driver use the
blk_dread() and blk_dwrite() respectively. The blk_* APIs read and write
to the devices in terms of the device block size. However, the FAT
driver reads in terms of the device block size (from fat_set_blk_dev and
read_bootsectandvi) and sector size in the rest of the places.

This causes buffer overflows or partial reads when the FAT sector size
is not equal to device block size. Fix this by using blk_dread in
fat_set_blk_dev and read_bootsectandvi instead of disk_read. And update
disk_read/disk_write to handle FAT sector size and block size mismatch.

Tested on
	blksz | FAT sector size
	------+----------------
	4096  | 4096
	512   | 512
	4096  | 512
	512   | 4096

CI test results
---------------
	https://github.com/u-boot/u-boot/pull/871
	All checks have passed
	93 successful checks
	No conflicts with base branch

Code size change info
---------------------
       arm: (for 1/1 boards) all +32.0 text +32.0
            qemu_arm       : all +32 text +32
               u-boot: add: 0/0, grow: 2/0 bytes: 24/0 (24)
                 function                                   old     new   delta
                 read_bootsectandvi                         420     432     +12
                 fat_set_blk_dev                            204     216     +12

   aarch64: (for 1/1 boards) all +12.0 rodata -8.0 text +20.0
            qemu_arm64     : all +12 rodata -8 text +20
               u-boot: add: 0/0, grow: 2/0 bytes: 20/0 (20)
                 function                                   old     new   delta
                 read_bootsectandvi                         408     420     +12
                 fat_set_blk_dev                            204     212      +8

   aarch64: (for 1/1 boards) all -2.0 data -8.0 rodata +6.0
            qcom_qcs9100   : all -2 data -8 rodata +6
               u-boot: add: 1/-1, grow: 8/-1 bytes: 708/-224 (484)
                 function                                   old     new   delta
                 disk_rw                                      -     628    +628
                 read_bootsectandvi                         408     428     +20
                 fat_itr_root                               500     520     +20
                 get_cluster                                376     388     +12
                 set_contents                              2076    2084      +8
                 fat_set_blk_dev                            204     212      +8
                 static.set_fatent_value                    536     540      +4
                 get_fatent                                 420     424      +4
                 fat_next_cluster                           368     372      +4
                 disk_read                                  100       -    -100
                 disk_write                                 132       8    -124

Link: https://lore.kernel.org/r/20260224035000.1617869-1-varadarajan.narayanan@oss.qualcomm.com