arch/arm/lib/bootm-fdt.c: Guard the include of <asm/armv7.h>
With d6b72da0 we started including this file unconditionally. This
isn't allowed in a file that we also use on armv8. This will get
cleaned up a bit better once we really start using these same features
(and have similar fdt updates needed) on armv8.
Signed-off-by: Tom Rini <trini@konsulko.com>