[ARM] 3399/1: Fix link problem when CONFIG_PRINTK is disabled

Patch from Malcolm Parsons

Printking a backtrace requires printk, so disable backtrace code
when printk is disabled.

Without this patch, a kernel with CONFIG_PRINTK disabled does not link:

arch/arm/lib/lib.a(backtrace.o): In function `c_backtrace':
arch/arm/lib/backtrace.S:(.text+0x108): undefined reference to `printk'
arch/arm/lib/backtrace.S:(.text+0x11c): undefined reference to `printk'
arch/arm/lib/lib.a(backtrace.o):(.fixup+0x8): undefined reference to `printk'
Signed-off-by: NMalcolm Parsons <malcolm.parsons@gmail.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/lib/backtrace.S

@@ -29,7 +29,7 @@ ENTRY(__backtrace)
 
 ENTRY(c_backtrace)
 
-#ifndef CONFIG_FRAME_POINTER
+#if !defined(CONFIG_FRAME_POINTER) || !defined(CONFIG_PRINTK)
 		mov	pc, lr
 #else