CHROMIUM: camx: fix inconsistent lock state at cam_context_prepare_dev_to_hw()

Disable BH so that we don't that lock from soft-irq context.

UPSTREAM-TASK=b:274966069
BUG=b:361674539
TEST=camera.HAL3Preview on coachz with lockdep enabled
TEST=camera.HAL3StillCapture on coachz with lockdep

Change-Id: Ifd862f991bf6bb0c3e219e1e8e2d4af8538ebd66
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/5806140


Reviewed-by: Ricardo Ribalda <ribalda@chromium.org>
(cherry picked from commit 192678a74123e22ec05445545358a353981a8ee8)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/5826170


Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Signed-off-by: Hubert Mazur <hmazur@google.com>