main: Fix texObj->Immutable flag update in _mesa_texture_image_multisample.
main: Fix texObj->Immutable flag update in _mesa_texture_image_multisample.

Reviewed-by: Anuj Phogat <e2026475996c48f0b97fd37e84129b3912980428@gmail.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler