arm64: perf: fix array out of bounds access in armpmu_map_hw_event()

This is a port of d9f966357b14 ("ARM: 7810/1: perf: Fix array out of
bounds access in armpmu_map_hw_event()") to arm64, which fixes an oops
in the arm64 perf backend found as a result of Vince's fuzzing tool.

Cc: <stable@vger.kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Git-commit: 868f6fea8fa63f09acbfa93256d0d2abdcabff79
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


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