drivers: llcc: Remove access to unwanted registers

Retain on power collapse and capacity allocation are controlled on
the secure side. Remove the access from non-secure side. Data ram
ecc is enabled by default and the bit to enable it is removed from
COMMON_CFG0 register.

Change-Id: I4dd40be4af668b4b7583b5e88ea4083b477ad4f1
Signed-off-by: Channagoud Kadabi <ckadabi@codeaurora.org>
Signed-off-by: Runmin Wang <runminw@codeaurora.org>