radeon: Advertise correct GL_QUERY_COUNTER_BITS/GL_SAMPLES_PASSED value

radeon: Advertise correct GL_QUERY_COUNTER_BITS/GL_SAMPLES_PASSED value

Commit b765119c changed the default value of all the counter bits to
64.  However, older hardware only has 32 counter bits.

This has only been build-tested.  We don't have any tests that verify
the advertised value against implementation behavior, so I don't know
what additional testing could be done.

NOTE: It appears that many Gallium drivers (at least r300 and i915g)
have the same problem, but I don't see a way for the state-tracker to
determine the counter size.  Marek says, "For Gallium, a new PIPE_CAP or
new get_xxx_param function will be needed."

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>