ARM: always perform per-CPU GIC init

The current code in ARMv8's lowlevel_init() skips the per-CPU GIC
initialization ifndef CONFIG_ARMV8_MULTIENTRY. However, the per-CPU init
should always occur; it's just the one-time init that should only happen
on the master.

Once this consideration is taken into account, the only difference between
the paths when CONFIG_ARMV8_MULTIENTRY is undefined/defined is the use of
branch_if_slave. Naively, any unified code would need to invoke this
conditionally upon ifdef CONFIG_ARMV8_MULTIENTRY. However, branch_if_slave
already checks CONFIG_ARMV8_MULTIENTRY and does nothing if it isn't
defined, so we don't even need that ifdef at the call site.

Reported-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>

arch/arm/cpu/armv8/start.S

@@ -201,15 +201,6 @@ ENDPROC(apply_core_errata)
 WEAK(lowlevel_init)
 	mov	x29, lr			/* Save LR */
 
-#ifndef CONFIG_ARMV8_MULTIENTRY
-#if defined(CONFIG_GICV2) || defined(CONFIG_GICV3)
-	/*
-	 * For single-entry systems the lowlevel init is very simple.
-	 */
-	ldr	x0, =GICD_BASE
-	bl	gic_init_secure
-#endif
-#else /* CONFIG_ARMV8_MULTIENTRY is set */
 #if defined(CONFIG_GICV2) || defined(CONFIG_GICV3)
 	branch_if_slave x0, 1f
 	ldr	x0, =GICD_BASE
@@ -222,7 +213,6 @@ WEAK(lowlevel_init)
 	ldr	x0, =GICD_BASE
 	ldr	x1, =GICC_BASE
 	bl	gic_init_secure_percpu
-#endif
 #endif
 
 	branch_if_master x0, x1, 2f