kernel: move fnv1a hash from hashtable.c to util.h

kernel-src/include/util.h

@@ -2,6 +2,7 @@
 #define _UTIL_H
 
 #include <stdint.h>
+#include <stddef.h>
 
 #define UTIL_ZEROBUFFERSIZE (1024 * 64)
 
@@ -20,6 +21,23 @@ static inline long min(long x, long y) {
 	return x > y ? y : x;
 }
 
+#define FNV1PRIME  0x100000001b3ull
+#define FNV1OFFSET 0xcbf29ce484222325ull
+
+// FNV-1a hash implementation
+static inline uint64_t fnv1ahash(void *buffer, size_t size) {
+	uint8_t *ptr = buffer;
+	uint8_t *top = ptr + size;
+	uint64_t h = FNV1OFFSET;
+
+	while (ptr < top) {
+		h ^= *ptr++;
+		h *= FNV1PRIME;
+	}
+
+	return h;
+}
+
 extern uint8_t util_zerobuffer[];
 
 #endif