Improve the debugging support of the PS3 bootwraper code:
o Increase the size of the PS3 bootwrapper overlay from 256 to 512 bytes to
allow for more debugging code in the overlay.
o Use the dot symbol to set the size of __system_reset_overlay. The
assembler will then emit an error if the overlay code is too big.
o Remove some unused instructions.
o Update the text describing the PS3 bootwrapper overlay.
o Add a check for null pointer writes.
o Change hcall return value from s64.
Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>