dummyflasher.c: Prevent use-after-free bug

The memory for the `status` string is aliased by the `endptr` pointer.
Moreover, `errno` could have been modified by the call to `free()`.
Therefore, only free the former when there are no more uses of either.

Change-Id: I1b56834004fe18918213a7df0a09a8a7ecb56985
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/54909
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>
1 file changed