V4 RegAlloc: do not add duplicate register hints

Change-Id: Id4b9b9481fe5c6b9cdab077b3957a0442fcff547
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
V4 IR: fix printing with register information.

The register numbers for non-FP registers overlap with the FP ones. So
when keying a single mapping on number, this resulted in the FP ones
overwriting the non-FP ones. This patch splits the mapping in two.

Change-Id: I95042b52a423eaaa96ed55d6c8ef12a2eb99f191
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
V4 IR: change debug code enabling to use compile-time constants

This will make sure that debug code gets compiled/checked, even when
it is disabled. An optimized build will remove the code.

Change-Id: Ia32de550ea95c44afa5ed84bc17cfeeada06f2f4
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>