media: venus: mark PM functions as __maybe_unused

Without PM support, gcc warns about two unused functions:

platform/qcom/venus/core.c:146:13: error: 'venus_clks_disable' defined but not used [-Werror=unused-function]
platform/qcom/venus/core.c:126:12: error: 'venus_clks_enable' defined but not used [-Werror=unused-function]

The problem as usual are incorrect #ifdefs, so the easiest fix
is to do away with the #ifdef completely and mark the suspend/resume
handlers as __maybe_unused, which they are.

Fixes: af2c3834 ("[media] media: venus: adding core part and helper functions")

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>