arm64: Make do_bad_area() function static

This function is only called from arch/arm64/mm/fault.c.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Git-commit: 59f67e16e6b79697241c3fd030e3da300377893e
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Ian Maund <imaund@codeaurora.org>