drivers/char/random.c: make primary_crng static

Since the definition of struct crng_state is private to random.c, and
primary_crng is neither declared or used elsewhere, there's no reason
for that symbol to have external linkage.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

drivers/char/random.c

@@ -415,7 +415,7 @@ struct crng_state {
 	spinlock_t	lock;
 };
 
-struct crng_state primary_crng = {
+static struct crng_state primary_crng = {
 	.lock = __SPIN_LOCK_UNLOCKED(primary_crng.lock),
 };