Issues with bios in mmu.js

[Akhil841]

The sole 0x4C in _bios should be 0x3C
One of the c's in a 0x3C is lowercase
The second 0xF2 in _bios should be 0xE2

Source: compared with actual game boy bios
(sharing an actual game boy bios is illegal, this disassembly is accurate though to my game boy bios dump)