UPSTREAM: drm/i915/display: Use int for entry setup frames

At least one TGL had regression when using u8 types
for entry setup frames calculation. So, let's switch
to use ints instead.

intel_psr_entry_setup_frames() function expects
to return u8 but since in case of error the error
code -ETIME is returned. This doesn't fit into u8
and hence the return value is not as expected.

Fixes: 2b981d57 ("drm/i915/display: Support PSR entry VSC packet to be transmitted one frame earlier")
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231113093737.358137-1-mika.kahola@intel.com


(cherry picked from commit a6865fe6)

BUG=b:308455498
TEST=Verify Asus PG32UQXR 4K160 mode on Rex using Big Joiner

Change-Id: I2d1911054af6a60bfa6bc290974a46a0afde41c1
Signed-off-by: Rakshith M O <rakshith.m.o@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/5802783


Reviewed-by: Manasi Navare <navaremanasi@chromium.org>
Reviewed-by: Sean Paul <sean@poorly.run>
Signed-off-by: Hubert Mazur <hmazur@google.com>