scsi: target: core: Fix integer overflow in UNMAP bounds check

scsi: target: core: Fix integer overflow in UNMAP bounds check

sbc_execute_unmap() checks LBA + range does not exceed the device capacity,
but does not guard against LBA + range wrapping around on 64-bit overflow.

Add an overflow check matching the pattern already used for WRITE_SAME in
the same file.

Fixes: 86d7182985d2 ("target: Add sbc_execute_unmap() helper")
Reported-by: Yuhao Jiang <danisjiang@gmail.com>
Signed-off-by: Junrui Luo <moonafterrain@outlook.com>
Link: https://patch.msgid.link/SYBPR01MB7881593C61AD52C69FBDB0BDAF7CA@SYBPR01MB7881.ausprd01.prod.outlook.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>