perf annotate: Sort list of recognised instructions

Currently the list of instructions recognised by perf annotate has to be
explicitly written in sorted order. This makes it easy to make mistakes
when adding new instructions. Sort the list of instructions on first
access.

Signed-off-by: Chris Ryder <chris.ryder@arm.com>
Acked-by: Pawel Moll <pawel.moll@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/4268febaf32f47f322c166fb2fe98cfec7041e11.1463676839.git.chris.ryder@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>