intel/isl: Fix map between sRGB and linear formats

Some SRGB formats don't get the expected linear counterparts in
isl_format_srgb_to_linear() in the generated isl_format_layout.c.

The replace() of string in python returns the unchanged input
string when no replacement occurred, so the first rule
('_SRGB', '') returns the original SRGB format name that passes
the following check unintendedly.

Another quirk is needed for a pair of formats not following
the patterns of other formats.

Signed-off-by: Zhang, Jianxun <jianxun.zhang@intel.com>
Reviewed-by: Nanley Chery <nanley.g.chery@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22247>

src/intel/isl/gen_format_layout.py

@@ -253,12 +253,14 @@ def get_srgb_to_linear_map(formats):
             ('_SRGB',   ''),
             ('SRGB',    'RGB'),
             ('U8SRGB',  'FLT16'),
+            # Quirk: ETC2_EAC_SRGB8_A8 -> ETC2_EAC_RGBA8
+            ('SRGB8_A8', 'RGBA8'),
         ]
 
         found = False
         for rep in replacements:
             rgb_name = fmt.name.replace(rep[0], rep[1])
-            if rgb_name in names:
+            if rgb_name in names and rgb_name != fmt.name:
                 found = True
                 yield fmt.name, rgb_name
                 break