pxa: Fix boot hang by avoiding vector relocation

Since commit 3ff46cc42b ("arm: relocate the exception vectors")
pxa does not boot anymore.

Add a specific relocate_vectors macro that skips the vector relocation,
as the pxa SoC does not provide RAM at the high vectors address
(0xFFFF0000), and (0x00000000) maps to ROM.

This allows pxa to boot again.

Cc: Marek Vasut <marex@denx.de>
Signed-off-by: Andrew Ruder <andrew.ruder@elecsyscorp.com>

arch/arm/cpu/pxa/Makefile

@@ -13,3 +13,4 @@ obj-$(CONFIG_CPU_PXA27X)	+= pxa2xx.o
 obj-y	+= cpuinfo.o
 obj-y	+= timer.o
 obj-y	+= usb.o
+obj-y	+= relocate.o

arch/arm/cpu/pxa/relocate.S

@@ -0,0 +1,23 @@
+/*
+ *  relocate - PXA270 vector relocation
+ *
+ *  Copyright (c) 2013  Albert ARIBAUD <albert.u.boot@aribaud.net>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <linux/linkage.h>
+
+/*
+ * The PXA SoC is very specific with respect to exceptions: it
+ * does not provide RAM at the high vectors address (0xFFFF0000),
+ * thus only the low address (0x00000000) is useable; but that is
+ * in ROM, so let's avoid relocating the vectors.
+ */
+	.section	.text.relocate_vectors,"ax",%progbits
+
+ENTRY(relocate_vectors)
+
+	bx	lr
+
+ENDPROC(relocate_vectors)