ARM: fix ifdef in ARMv8 lowlevel_init() again

Commit 11661193 ("ARM: fix ifdefs in ARMv8 lowlevel_init()")
accidentally inverted the logic of CONFIG_ARMV8_MULTIENTRY.

Fixes: 11661193 ("ARM: fix ifdefs in ARMv8 lowlevel_init()")
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NStephen Warren <swarren@nvidia.com>

arch/arm/cpu/armv8/start.S

@@ -216,7 +216,7 @@ WEAK(lowlevel_init)
 #endif
 #endif
 
-#ifndef CONFIG_ARMV8_MULTIENTRY
+#ifdef CONFIG_ARMV8_MULTIENTRY
 	branch_if_master x0, x1, 2f
 
 	/*