ARM: l2c: omap2: remove explicit non-secure access bits

Since we now always enable NS access to the unlock registers, this can
be removed from OMAP4.  Remove the NS access bit for the interrupt
registers from OMAP4 as well - nothing in the kernel accesses that yet,
and we can add it in core code when we have the need.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>