arch/arm64: Fix compilation without CONFIG_SMP

Compilers aren't happy with a declaration of boot_cpu() after defining
boot_cpu to 1.

Change-Id: I22d0db61646f3e226e5996fa94223ffbb6b760e5
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: http://review.coreboot.org/10696
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
1 file changed