spu-precise: fix double-precision floating-point exception checks

[scribam]

Results based on this test: https://github.com/RPCS3/ps3autotests/blob/master/tests/cpu/spu_generic/spu_test_0.spu.cpp

[elad335]

My original intention was to read the mxcsr register once and use its value to determine the exception flags raised. If the values being used are wrong, fix them instead.

[scribam]

Thanks for the review. PR updated with your recommendation.

[stan0danny]

i'm afraid, i saw rpcs3 update is infamous 2009 before fps 2.45 - 5,10 and after fps 0.43 , my laptop nvidia 940m 2gb , i7 5500u , ram 16 gb . you fixing rpcs3 sometime ?

[AniLeo]

Precise modes are not meant to have playable speeds.

[stan0danny]

ohhh :(