parisc/slab: cleanup after /proc/slab_allocators removal

The commit 7878c231 ("slab: remove /proc/slab_allocators")
removes DEBUG_SLAB_LEAK config everywhere but a parisc config.
It doesn't look intentional. Fix it.
Signed-off-by: Yury Norov <ynorov@marvell.com>
Signed-off-by: Helge Deller <deller@gmx.de>

arch/parisc/configs/c8000_defconfig

@@ -225,7 +225,6 @@ CONFIG_UNUSED_SYMBOLS=y
 CONFIG_DEBUG_FS=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_SLAB=y
-CONFIG_DEBUG_SLAB_LEAK=y
 CONFIG_DEBUG_MEMORY_INIT=y
 CONFIG_DEBUG_STACKOVERFLOW=y
 CONFIG_PANIC_ON_OOPS=y