cmd/compile: set PPC64's MAXWIDTH as other architectures
PPC64's MAXWIDTH is set as 1<<60 whereas on other 64-bit
architetures it is set as 1<<50. Set to 1<<50 for consistency. The
toolchain cannot handle such large program anyway.
May fix PPC64 build.
Change-Id: Ic3972a089b2f14a96e4ded57ef218d763c924a6a
Reviewed-on: https://go-review.googlesource.com/c/go/+/368955
Trust: Cherry Mui <cherryyz@google.com>
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Dan Scales <danscales@google.com>