ARM: configs: aspeed: Add support for USB flash drives

ARM: configs: aspeed: Add support for USB flash drives

Add support to detect USB flash drives and create the /dev/sd* devices.
Also add support for vfat to support USB drives formatted as FAT32.
This support will be used to enable firmware updates via USB flash
drives where the firmware image is stored in the USB drive and it's
plugged into the BMC USB port.

Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
Tested-by: Adriana Kobylak <anoo@us.ibm.com>
Link: https://lore.kernel.org/r/20211112202931.2379145-1-anoo@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>