Docs/Makefile: change 'which' to 'command -v'

The "which" command is not a posix command. Additionally, if a file
is not found, it outputs "command not found", so when checking to see
if the response is "", that doesn't work.

"command -v" is a posix compliant replacement that doesn't put out any
text if the command is not found, so is more suitable in this case
anyway.

Signed-off-by: Martin Roth <gaumless@gmail.com>
Change-Id: I22207e818c847d50998f90c9abd55a3cb4bb2ab3
Reviewed-on: https://review.coreboot.org/c/coreboot/+/72922
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <felixsinger@posteo.net>

0 files changed, 0 insertions, 0 deletions