ticket 954
Pull up following revision(s) (requested by tsutsui in ticket #955):
	sys/arch/mvmeppc/stand/libsa/Makefile.inc: revision 1.2
	sys/arch/mvmeppc/stand/Makefile.booters: revision 1.13
	sys/arch/mvmeppc/stand/libsa/Makefile: revision 1.11
Explicitly link srt0.o (Standalone RunTime startup code) first.
Taken from the similar fix of mvme68k:
http://mail-index.netbsd.org/source-changes/2013/09/21/msg047819.html
MVME PROM requires raw binaries (by objcopy -O binary) so we have to
make sure the entry point is located at the first address of the binaries.
The original changes to switch to using MI libsa is:
http://mail-index.netbsd.org/source-changes/2011/01/02/msg016563.html
Should be pulled up to netbsd-6 branches.
(though untested since there seems no users of mvmeppc)
ticket 955