ARM: 8295/1: fix v7M build for !CONFIG_PRINTK

Minimal builds for v7M are broken when printk is disabled. The caller is
assembly so add the necessary ifdef around the call.
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/entry-v7m.S

@@ -22,10 +22,12 @@
 
 __invalid_entry:
 	v7m_exception_entry
+#ifdef CONFIG_PRINTK
 	adr	r0, strerr
 	mrs	r1, ipsr
 	mov	r2, lr
 	bl	printk
+#endif
 	mov	r0, sp
 	bl	show_regs
 1:	b	1b