flashrom.c: Allow to use select_erase_function() for explicit erase

When we are explicitly called to erase, we simply select every block
that overlaps the given region.

Change-Id: I2085855adb4406fdc6d6e813ea4bd912db13473d
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/72561
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
1 file changed