Replace or remove invalid characters in comments
Fixes flawfinder-sast failures: Error: encoding error in ./src/xg47_videohw.c 'utf-8' codec can't decode byte 0x92 in position 1980: invalid start byte Error: encoding error in ./src/xg47_regs.h 'utf-8' codec can't decode byte 0xa8 in position 6460: invalid start byte Error: encoding error in ./src/xg47_regs.h 'utf-8' codec can't decode byte 0xe7 in position 4716: invalid continuation byte Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>