Platform: Polaris: Remove unused MPC reset fix

The MPC config does not have to be set to secure manually
before reset, so removed leftover comments and functions.
The reset hook has been removed before in the 5671755b
commit.

Change-Id: Iabc35b50eb98d6a1a4750e4702e4fc337c942aa9
Signed-off-by: Bence Balogh <bence.balogh@arm.com>
2 files changed