ARM: 8160/1: drop warning about return_address not using unwind tables

The warning was introduced in 2009 (commit 4bf1fa5a34aa ([ARM] 5613/1:
implement CALLER_ADDRESSx)). The only "problem" here is that
CALLER_ADDRESSx for x > 1 returns NULL which doesn't do much harm.

The drawback of implementing a fix (i.e. use unwind tables to implement CALLER_ADDRESSx) is that much of the unwinder code would need to be marked as not
traceable.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/return_address.c

@@ -59,10 +59,6 @@ void *return_address(unsigned int level)
 
 #else /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) */
 
-#if defined(CONFIG_ARM_UNWIND)
-#warning "TODO: return_address should use unwind tables"
-#endif
-
 #endif /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) / else */
 
 EXPORT_SYMBOL_GPL(return_address);