fix(dracut-functions.sh): convert mmcblk to the real kernel module name
In some x86_64 platforms such as Intel Elkhartlake, an issue of missing
necessary modules due to udevadm drivers field unmatch the real kernel module
name is found:
$ udevadm info -a /dev/block/179:1
looking at parent device '/devices/pci0000:00/0000:00:1a.0/mmc_host/mmc0/mmc0:0001':
KERNELS=="mmc0:0001"
SUBSYSTEMS=="mmc"
DRIVERS=="mmcblk"
....
The DRIVERS field, aka mmcblk will be given to instmods to install the
corresponding mmc_block.ko kernel module. However mmc_block.ko cannot be
selected by string mmcblk, as a result, mmc_block.ko cannot be installed
in hostonly-mode strict, which will fail to bootup the machine such as in
kdump cases: