PPC64, Replace body of generate_store_FPRF with C helper function.

PPC64, Replace body of generate_store_FPRF with C helper function.

The function calculates the floating point condition code values
and stores them into the floating point condition code register.
The function is used by a number of instructions. The calculation
generates a lot of Iops as it much check the operatds for NaN, SNaN,
zero, dnorm, norm and infinity. The large number of Iops exhausts
temporary memory.