ARM: 8046/1: proc: add support for the Cortex-A17 processor

Cortex-A17 has identical initialisation requirements to Cortex-A12, so
hook it up in proc-v7.S in the same way.

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