[Tweak] Fix Namco 163 naming

[N-SPC700]

While it's often debated whether or not the Namco 163 is actually called the "N163" or "C163", Atlus sound programmer Tsukasa Masuko calls it the "Custom 163" in this video, which is also the same naming scheme as every other Namco chip of the era (which was also marked as "Custom XXX" in some information, then "CUSXXX" and then just the part number itself). Said individual also created the sound driver that all of Atlus' expansion sound games used.

The request is, to fix the naming scheme and relevant icons/graphics for FT to properly fit what would essentially be the "correct" name of the chip. Would also affect #308 if that is to be implemented as well, as it too is a Namco Custom chip.