kmemleak: Allow kmemleak to be built on powerpc

Very lightly tested, doesn't crash the kernel.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

lib/Kconfig.debug

@@ -338,7 +338,7 @@ config SLUB_STATS
 
 config DEBUG_KMEMLEAK
 	bool "Kernel memory leak detector"
-	depends on DEBUG_KERNEL && EXPERIMENTAL && (X86 || ARM) && \
+	depends on DEBUG_KERNEL && EXPERIMENTAL && (X86 || ARM || PPC) && \
 		!MEMORY_HOTPLUG
 	select DEBUG_FS if SYSFS
 	select STACKTRACE if STACKTRACE_SUPPORT