dummyflasher.c: Only write back emulated image if modified

When the image is not modified, there is no point in writing it back.
In fact we may not have file permissions to do so.

Signed-off-by: Namyoon Woo <namyoon@google.com>
Change-Id: I3bf2d7edb28a9a1e5406b67a88a0ee6e07db83e3
Reviewed-on: https://review.coreboot.org/c/flashrom/+/44907
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
1 file changed