#51 fix an AARCH64 gcc error with 'const' qualifers

[Pete Batard]

• aarch64-linux-gnu-gcc on Debian/Sid fails lib compilation with:
  lib/aarch64/initplat.c:44:35: error: initialization discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers]
• This patch fixes it

[Nigel Croxon]

Thank you for the patch Pete.

commit 8071303f52f376de3357b223ce8905598de1f913