update section names to comply with rgbds redefinitions

so bentley's gone and renamed everything since a bunch of new section types were added anyway, so if we want wram/vram/sram banks we gotta cut off outdated versions of rgbds. pokecrystal uses all three so this is inevitable

a rundown of whats changed:

HOME -> ROM0
DATA, CODE -> ROMX
BSS -> WRAM0, WRAMX

new to rgbds are banked VRAM and SRAM