iris: Align fast clear color state buffer to a page.

On gen11 and older, compressed images are tiled and aligned to 4K. On
gen12 this 4K alignment restriction was removed. However, only aligning
the fast clear color buffer to 64B (a cacheline, as it's on the
documentation) is causing some bugs where the fast clear color is not
converted during the fast clear operation. Aligning things to 4K seems
to fix it.

v2: Fix typo case in the comment (Nanley)
v3: Rebase and fix conflicts.
v4: Fix rebase mistake (Nanley).

Reviewed-by: Nanley Chery <nanley.g.chery@intel.com>
49 jobs for !2530 with tgl-clear-color-alignment in 51 minutes and 20 seconds (queued for 23 minutes and 23 seconds)
merge request