mesa: added gl_program::IndirectRegisterFiles field

Now drivers, etc. can know which register files are accessed with
indirect addressing.  Before we just checked gl_program::NumAddressRegs
but didn't know if that was the constant buffer, temp regs, or what.

The only user of this new field so far will be the gallium state tracker.
diff --git a/src/mesa/program/program.c b/src/mesa/program/program.c
index cf46095..d99584d 100644
--- a/src/mesa/program/program.c
+++ b/src/mesa/program/program.c
@@ -512,6 +512,7 @@
    if (prog->Attributes)
       clone->Attributes = _mesa_clone_parameter_list(prog->Attributes);
    memcpy(clone->LocalParams, prog->LocalParams, sizeof(clone->LocalParams));
+   clone->IndirectRegisterFiles = prog->IndirectRegisterFiles;
    clone->NumInstructions = prog->NumInstructions;
    clone->NumTemporaries = prog->NumTemporaries;
    clone->NumParameters = prog->NumParameters;