Move generic architectural setup out of blx_plat_arch_setup().

blx_plat_arch_setup() should only perform platform-specific
architectural setup, e.g. enabling the MMU.  This patch moves
generic architectural setup code out of blx_plat_arch_setup().

Change-Id: I4ccf56b8c4a2fa84909817779a2d97a14aaafab6
diff --git a/arch/aarch64/cpu/cpu_helpers.S b/arch/aarch64/cpu/cpu_helpers.S
index 600b72f..76edaa3 100644
--- a/arch/aarch64/cpu/cpu_helpers.S
+++ b/arch/aarch64/cpu/cpu_helpers.S
@@ -39,14 +39,9 @@
 	mov	x19, x30 // lr
 
 	/* ---------------------------------------------
-	 * As a bare minimal enable the SMP bit and the
-	 * I$ for all aarch64 processors. Also set the
-	 * exception vector to something sane.
+	 * As a bare minimal enable the SMP bit.
 	 * ---------------------------------------------
 	 */
-	adr	x0, early_exceptions
-	bl	write_vbar
-
 	bl	read_midr
 	lsr	x0, x0, #MIDR_PN_SHIFT
 	and	x0, x0, #MIDR_PN_MASK
@@ -59,8 +54,4 @@
 	orr	x0, x0, #CPUECTLR_SMP_BIT
 	bl	write_cpuectlr
 smp_setup_end:
-	bl	read_sctlr
-	orr	x0, x0, #SCTLR_I_BIT
-	bl	write_sctlr
-
 	ret	x19