lib: consolidate DEBUG_STACK_USAGE option

Most arches define CONFIG_DEBUG_STACK_USAGE exactly the same way.  Move it
to lib/Kconfig.debug so each arch doesn't have to define it.  This
obviously makes the option generic, but that's fine because the config is
already used in generic code.

It's not obvious to me that sysrq-P actually does anything caution by
keeping the most inclusive wording.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Richard Weinberger <richard@nod.at>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/mips/Kconfig.debug

@@ -76,15 +76,6 @@ config DEBUG_STACKOVERFLOW
 	  provides another way to check stack overflow happened on kernel mode
 	  stack usually caused by nested interruption.
 
-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 and sysrq-P debug output.
-
-	  This option will slow down process creation somewhat.
-
 config SMTC_IDLE_HOOK_DEBUG
 	bool "Enable additional debug checks before going into CPU idle loop"
 	depends on DEBUG_KERNEL && MIPS_MT_SMTC