flashrom.c: Introduce gran_to_bytes()

Change-Id: Ib41f9581060350f41620e9e377b9bafa58677882
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/72545
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
1 file changed