Revert "armv7m: Disable D-cache when booting nommu(ARMv7M) Linux kernel"

The author of the commit discovered later on that this was already being
done in cleanup_before_linux() on arch/arm/cpu/armv7m/cpu.c.

This reverts commit 8f079ccc.

Signed-off-by: Tom Rini <trini@konsulko.com>