powerpc/head_check: use stdout for error messages

Prefer stderr instead of stdout for error messages.
This is a good practice and can help CI error detecting and
reporting (0day in this case).

Signed-off-by: Randy Dunlap <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

1 file changed