[U-Boot] Please revert unnecessary dcache_disable() commit

Hello,

commit 8f079cccb369995e46a2ab530d5d60b88c1e70bb ("armv7m: Disable D-cache when booting nommu(ARMv7M) Linux kernel") added dcache_disable(), but this function is existed at cleanup_before_linux() on arch/arm/cpu/armv7m/cpu.c. Could you revert this commit.

thanks, Toshifumi NISHINAGA