mesa/formatquery: Added SRGB_{READ,WRITE} <pname> queries

mesa/formatquery: Added SRGB_{READ,WRITE} <pname> queries

From the ARB_internalformat_query2 specification:

   "- SRGB_READ: The support for converting from sRGB colorspace on read
      operations (see section 3.9.18) from the resource is returned in
      <params>.
      Possible values returned are FULL_SUPPORT, CAVEAT_SUPPORT, or NONE.
      If the resource or operation is not supported, NONE is returned.

    - SRGB_WRITE: The support for converting to sRGB colorspace on write
      operations to the resource is returned in <params>.
      This indicates that writing to framebuffers with this internalformat
      will encode to sRGB color spaces when FRAMEBUFFER_SRGB is enabled (see
      section 4.1.8).
      Possible values returned are FULL_SUPPORT, CAVEAT_SUPPORT, or NONE.
      If the resource or operation is not supported, NONE is returned."

Reviewed-by: Dave Airlie <airlied@redhat.com>