mesa: provide default implementation of QuerySamplesForFormat

mesa: provide default implementation of QuerySamplesForFormat

Previously at least i915 failed to provide an implementation, but
exposed ARB_internalformat_query anyway, leading to crashes when
QueryInternalformativ was called.

Default implementation just returns 1 for everything, so is suitable for
any driver which does not support multisampling.

V2: - Move from intel to core mesa.

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>