This patch introduces floating point registers used for 32-bit
operations, and basic handling of FP values in operands. It is
partial work needed as a base for further work.

R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/1993993004 .

Patch from Srdjan Obucina <Srdjan.Obucina@imgtec.com>.