[ARM] CONFIG_DEBUG_STACK_USAGE

In early 2.6 days stack utilization instrumentation was made
configurable. Seems that arm misses the DEBUG_STACK_USAGE option.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Kconfig.debug

@@ -43,6 +43,12 @@ config DEBUG_ERRORS
 	  you are concerned with the code size or don't want to see these
 	  messages.
 
+config DEBUG_STACK_USAGE
+	bool "Enable stack utilization instrumentation"
+	depends on DEBUG_KERNEL
+	help
+	  Enables the display of the minimum amount of free stack which each
+	  task has ever had available in the sysrq-T output.
 
 # These options are only for real kernel hackers who want to get their hands dirty.
 config DEBUG_LL