i965/screen: Allow modifiers on sRGB formats

This effectively reverts a2669349 which
was a misguided attempt at protecting intel_query_dma_buf_modifiers from
invalid formats.  Unfortunately, in some internal EGL cases, we can get
an SRGB format validly in this function.  Rejecting such formats caused
us to not allow CCS in some cases where we should have been allowing it.
This regressed the performance of some SynMark tests as well as GfxBench
ALU2, Tessellation and Manhattan 3.0 tests

There's some question of whether or not we really should be using SRGB
"fourcc" formats that aren't actually in drm_foucc.h but there's not
much harm in allowing them through here.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107223


Fixes: a2669349 "i965/screen: Return false for unsupported..."
Tested-By: Eero Tamminen <eero.t.tamminen@intel.com>
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>
(cherry picked from commit d9cf4308)