Switch to eabi assembly, remove fix_asm.py, clean link with zero ABI warnings

(Yes my toolchain probably is still broken)

- Assembly now uses -mabi=eabi matching original ELF flags (eabi64)
- Removed fix_asm.py from post_split.sh (sd/ld assemble correctly with eabi)
- Replaced objcopy binary rule with incbin for consistent ELF flags
- Assembly stays unmodified from splat output
- Zero byte differences vs original .text verified
- Added sceVif1PkTerminate forward declaration
- Updated sceVif1PkCnt to save Terminate return value"

Author: ValakTurtle