printk/cache: mark printk_once test variable __read_mostly

Add #include <linux/cache.h> to define __read_mostly.

Convert cache.h to use uapi/linux/kernel.h instead
of linux/kernel.h to avoid recursive #includes.

Convert the ALIGN macro to __ALIGN_KERNEL.

printk_once only sets the bool variable tested
once so mark it __read_mostly.

Neaten the alignment so it matches the rest of the
pr_<level>_once #defines too.

Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/cache.h b/include/linux/cache.h
index 4c570653..17e7e82 100644
--- a/include/linux/cache.h
+++ b/include/linux/cache.h
@@ -1,11 +1,11 @@
 #ifndef __LINUX_CACHE_H
 #define __LINUX_CACHE_H
 
-#include <linux/kernel.h>
+#include <uapi/linux/kernel.h>
 #include <asm/cache.h>
 
 #ifndef L1_CACHE_ALIGN
-#define L1_CACHE_ALIGN(x) ALIGN(x, L1_CACHE_BYTES)
+#define L1_CACHE_ALIGN(x) __ALIGN_KERNEL(x, L1_CACHE_BYTES)
 #endif
 
 #ifndef SMP_CACHE_BYTES