Replace gl_geom_attrib enum with gl_varying_slot.

This patch makes the following search-and-replace changes:

gl_geom_attrib -> gl_varying_slot
GEOM_ATTRIB_* -> VARYING_SLOT_*
GEOM_BIT_* -> VARYING_BIT_*

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Tested-by: Brian Paul <brianp@vmware.com>

src/mesa/program/program.c

@@ -936,7 +936,7 @@ _mesa_valid_register_index(const struct gl_context *ctx,
       case MESA_SHADER_FRAGMENT:
          return index < FRAG_ATTRIB_VAR0 + (GLint) ctx->Const.MaxVarying;
       case MESA_SHADER_GEOMETRY:
-         return index < GEOM_ATTRIB_VAR0 + (GLint) ctx->Const.MaxVarying;
+         return index < VARYING_SLOT_VAR0 + (GLint) ctx->Const.MaxVarying;
       default:
          return GL_FALSE;
       }