Patch implements improvements and instruction encodings for many COP1 instructions for handling floating point values.

Patch covers load, store, basic arithmetic, data movement for FPR<->FPR, GPR<->FPR, FPR<->GPR, and format conversion instructinos.

Added instruction encodings:
Load: lb, lh, lwc1, ldc1
Store: sb, sh, swc1, sdc1
FP arith: abs_d, abs_s, add_d, add_s, div_d, div_s, mul_d, mul_s, sqrt_d, sqrt_s, sub_d, sub_s
FP movs: mfc1, mov_d, mov_s, movn_d, movn_s, movz_d, movz_s, mtc1
Conversion: cvt_d_l, cvt_d_s, cvt_d_w, cvt_s_d, cvt_s_l, cvt_s_w, trunc_l_d, trunc_l_s, trunc_w_d, trunc_w_s

R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/2341713003 .

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