ARM: dts: Move omap5 mmio-sram out of l3 interconnect

We need mmio-sram early for omap4_sram_init() for IO barrier init, and
will be moving l3 interconnect to probe with simple-pm-bus that probes
at module_init() time. So let's move mmio-sram out of l3 to prepare for
that.

Otherwise we will get the following after probing the interconnects with
simple-pm-bus:

omap4_sram_init:Unable to get sram pool needed to handle errata I688

Signed-off-by: Tony Lindgren <tony@atomide.com>