Documentation: update kmemleak supported archs

Instead of listing the architectures that are supported by
kmemleak in Documentation/kmemleak.txt, just refer people to
the list of supported architecutures in lib/Kconfig.debug so
that Documentation/kmemleak.txt does not need more updates
for this.

Signed-off-by: Maxin B. John <maxin.john@gmail.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/kmemleak.txt

@@ -11,7 +11,9 @@ with the difference that the orphan objects are not freed but only
 reported via /sys/kernel/debug/kmemleak. A similar method is used by the
 Valgrind tool (memcheck --leak-check) to detect the memory leaks in
 user-space applications.
-Kmemleak is supported on x86, arm, powerpc, sparc, sh, microblaze and tile.
+
+Please check DEBUG_KMEMLEAK dependencies in lib/Kconfig.debug for supported
+architectures.
 
 Usage
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