drm/i915/display: Consider adjusted_pixel_rate to be u64

drm/i915/display: Consider adjusted_pixel_rate to be u64

Consider adjusted_pixel_rate to be a u64 to match the return
type of mul_u32_u32() and avoid any compiler dependency for
do_div.

Fixes: 1676ecd303ac ("drm/i915: Compute CMRR and calculate vtotal")
Cc: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Cc: Suraj Kandpal <suraj.kandpal@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: intel-xe@lists.freedesktop.org
Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/r/20240619154207.GA1125704@thelio-3990X
Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240621073454.1421676-1-mitulkumar.ajitkumar.golani@intel.com