ARM: 8054/1: perf: add support for the Cortex-A17 PMU

The Cortex-A17 PMU is identical to that of the A12, so wire up a new
compatible string to the existing event structures.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>