perf_counter/powerpc: Fix cache event codes for POWER7

I had the codes for L1 D-cache load accesses and misses swapped
around, and the wrong codes for LL-cache accesses and misses.
This corrects them.

Reported-by: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
LKML-Reference: <19103.8514.709300.585484@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>