CHROMIUM: remoteproc: mediatek: Enable APU rproc building

Add Kconfig to build APU rproc driver.

UPSTREAM-TASK=b:379040514
BUG=b:365876446
TEST=emerge-rauru chromeos-kernel-6_6

Change-Id: Ie26008f6b17564b21faa7de18c4e26ce5978bcc9
Signed-off-by: Karl Li <karl.li@mediatek.corp-partner.google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/6166788


Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Fei Shao <fshao@chromium.org>
Commit-Queue: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Hsin-Te Yuan <yuanhsinte@chromium.org>
Signed-off-by: Hubert Mazur <hmazur@google.com>