[binutils-gdb] Remove some uses of MAX_REGISTER_SIZE uses from mn10300-linux-tdep.c

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT 146e6c5cc7b19ea56a033415511e38a2d0656e42 ***

Author: Alan Hayward <alan.hayward@arm.com>
Branch: master
Commit: 146e6c5cc7b19ea56a033415511e38a2d0656e42

Remove some uses of MAX_REGISTER_SIZE uses from mn10300-linux-tdep.c

gdb/
	* mn10300-linux-tdep.c (am33_supply_gregset_method): Use
	regcache->raw_supply_zeroed.