livepatch: Make 'klp_stack_entries' static

The 'klp_stack_entries' percpu array is only used in transition.c.  Make
it static.

Fixes: e92606fa ("livepatch: Convert stack entries array to percpu")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202305171329.i0UQ4TJa-lkp@intel.com/Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/5115752fca6537720700f4bf5b178959dfbca41a.1685488550.git.jpoimboe@kernel.org

kernel/livepatch/transition.c

@@ -15,7 +15,7 @@
 #include "transition.h"
 
 #define MAX_STACK_ENTRIES  100
-DEFINE_PER_CPU(unsigned long[MAX_STACK_ENTRIES], klp_stack_entries);
+static DEFINE_PER_CPU(unsigned long[MAX_STACK_ENTRIES], klp_stack_entries);
 
 #define STACK_ERR_BUF_SIZE 128