random: Add arch_has_random[_seed]()

Add predicate functions for having arch_get_random[_seed]*().  The
only current use is to avoid the loop in arch_random_refill() when
arch_get_random_seed_long() is unavailable.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/include/linux/random.h b/include/linux/random.h
index c2f08131..57fbbff 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -88,6 +88,10 @@
 {
 	return 0;
 }
+static inline int arch_has_random(void)
+{
+	return 0;
+}
 static inline int arch_get_random_seed_long(unsigned long *v)
 {
 	return 0;
@@ -96,6 +100,10 @@
 {
 	return 0;
 }
+static inline int arch_has_random_seed(void)
+{
+	return 0;
+}
 #endif
 
 /* Pseudo random number generator from numerical recipes. */