[U-Boot-Users] added dcache_disable(), dcache_status() stubs to ARM920T with no MMU support

Hello, list

I'm using U-Boot for ARM920T target to load ELF image on board. ELF loader ("common/cmd_elf.c") requires dcache_status() and dcache_disable() regardless of whether MMU is used or not.

I added two stubs in "cpu/arm920t/cpu.c" for the case when MMU is not used, but different CPUs may also be affected by this.

Best regards, Olexiy