fix(docs): update sme disconnect on power down

With `ERRATA_SME_POWER_DOWN` enabled we disconnect SME from
core to power down the core correctly, we actually don't disable sme.

Change-Id: I42b99bd5ef125868f55a2a3ef96c0ac1b054f509
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
1 file changed