As was described in the version 1.4 release notes, this deletes the
Makefile and supporting elements leaving Meson as the only supported
buildsystem.

Signed-off-by: Peter Marheine <pmarheine@chromium.org>
Change-Id: Ib3cf22cf636ef9b70527b734ffa34aead2a74edd
Reviewed-on: https://review.coreboot.org/c/flashrom/+/83673


Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>