glsl: Fix locations of variables in patch qualified interface blocks.

glsl: Fix locations of variables in patch qualified interface blocks.

As of commit d82f8d9772813949d0f5455cd0edad9003be0fb0, we actually
parse and attempt to handle the 'patch' qualifier on interface blocks.

This patch fixes explicit locations for variables in such blocks.
Without it, many program interface query dEQP/CTS tests hit this
assertion in ir_set_program_inouts.cpp

   if (is_patch_generic) {
      assert(idx >= VARYING_SLOT_PATCH0 && idx < VARYING_SLOT_TESS_MAX);
      bitfield = BITFIELD64_BIT(idx - VARYING_SLOT_PATCH0);
   }

because the location was incorrectly based on VARYING_SLOT_VAR0.

Note that most of the tests affected currently fail before they hit
this, due to confusion about what the program interface query name
of those resources should be.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>