efi_selftest: imply FAT, FAT_WRITE

efi_selftest_block_device accesses a FAT file system.
Signed-off-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: NAlexander Graf <agraf@suse.de>

lib/efi_selftest/Kconfig

 config CMD_BOOTEFI_SELFTEST
 	bool "Allow booting an EFI efi_selftest"
 	depends on CMD_BOOTEFI
+	imply FAT
+	imply FAT_WRITE
 	help
 	  This adds an EFI test application to U-Boot that can be executed
 	  with the 'bootefi selftest' command. It provides extended tests of