dts: cleanup usage of "flash" and "sram" compatible

Remove compatible = "flash" from any node that has it as this doesn't
have any well defined meaning right now.  Also update any compatible =
"sram" to be "mmio-sram" (as there's a binding in linux for this).

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
8 files changed