arm64: cpufeature: Pass capability structure to ->enable callback

In order to invoke the CPU capability ->matches callback from the ->enable
callback for applying local-CPU workarounds, we need a handle on the
capability structure.

This patch passes a pointer to the capability structure to the ->enable
callback.

Change-Id: Ia57e74fa144a701f5144b6661594e4f69f7b0140
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Patch-mainline: linux-arm-kernel @ 01/08/18, 9:32
[ckadabi@codeaurora.org: Resolved minor merge conflicts]
Signed-off-by: Channagoud Kadabi <ckadabi@codeaurora.org>