[PATCH 1/2] perf tools: fix a typo of a Power7 event name

[Sukadev Bhattiprolu]

Runzhen Wang [runzhen at linux.vnet.ibm.com] wrote:
| In the Power7 PMU guide:
| https://www.power.org/documentation/commonly-used-metrics-for-performance-analysis/
| PM_BRU_MPRED is referred to as PM_BR_MPRED.
| 
| This patch fix the typo by changing the name of the event in kernel and
| documentation accordingly.
| 
| Signed-off-by: Runzhen Wang <runzhen at linux.vnet.ibm.com>

Reviewed-by: Sukadev Bhattiprolu <sukadev at linux.vnet.ibm.com>