cmd/internal/obj/arm64: improve comment and signature of pcAlignPadLength
The function just calculates the number of needed padding bytes,
instead of actually carrying out the alignment operation. And it has
the context argument at the end of the argument list, while contexts
idiomatically come first. Indeed, this is the only case in
cmd/internal/obj where ctxt is not the only argument and does not come
first.
Fix those two nits; no functional change intended.
Suggested by Ian during review of CL 479815 (that introduces a copy of
this helper into the loong64 port).
Change-Id: Ieb221ead23282abe6e04804d537e1234c7ab21d0
Reviewed-on: https://go-review.googlesource.com/c/go/+/483155
Run-TryBot: Cherry Mui <cherryyz@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com>