util/u_math: Implement a logbase2 function for unsigned long

v2 (Karol Herbst <kherbst@redhat.com>):
* removed unneeded ll
* ll -> ull

Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>

src/util/bitscan.h

@@ -123,6 +123,17 @@ util_is_power_of_two_or_zero(unsigned v)
    return (v & (v - 1)) == 0;
 }
 
+/* Determine if an uint64_t value is a power of two.
+ *
+ * \note
+ * Zero is treated as a power of two.
+ */
+static inline bool
+util_is_power_of_two_or_zero64(uint64_t v)
+{
+   return (v & (v - 1)) == 0;
+}
+
 /* Determine if an unsigned value is a power of two.
  *
  * \note