rsx/fp: Fix precision clamping on MAD instruction

[kd-11]

RSX MAD instruction appears to be broken. Unlike other instructions, for this one only arg0 has clamping applied to it. However, when neg flag is set, the precision clamping works correctly. For example, consider this set of inputs (input clamping is set to [0,1] for all cases):
a) 1 * 100 + 0 = 100
b) 100 * 1 + 0 = 1
c) 1 * -100 + 0 = -1
d) 1* 1 + 100 = 101
etc

This fixes some rare graphical glitches such as the sea in one piece pirate warriors and the sky in GTA V. Also fixes post-processing in Crysis.

Fixes #2262

[MarioSonic2987]

Fixes these graphical issues in the following games:

Grand Theft Auto V - Grey sky

One Piece: Pirate Warriors - Broken water effects

[jackie1218]

The sky is now blue in MLB The Show 14, but other problems (unrelated to this pr) are still present.

https://cdn.discordapp.com/attachments/485204327800242177/711437885575921704/unknown.png

[i2puni]

Previously version ->
The game is fully playable. 2D versions plays perfectly. 3d version has missing graphics. For example, your default beam is not visible while you shoot in 3d mode. Full charge beam is visible.

this version ->
FIX!!!!!!! Good!!!!!!!!!!!