p_ftoi: Remove? / Let compiler decide rounding mode

[olajep]

Do we really need this function?

And can't we just let the compiler decide the rounding mode?

Reference:
https://github.com/parallella/pal/blob/master/src/math/p_ftoi.c

[aolofsson]

Let's check the compiler output on a couple of architectures before canceling funciton. Assumption is that it is not handled effectively with current compiler (at least for Epihany).

[WesleyCeraso]

Some GPU also do not support IEEE-754, it may be a problem. BTW, are PAL meant to support non-IEEE-754 devices?