Fix some overflow warnings

Author: palmer-dabbelt

drivers/clk/sifive/u54-prci.c

@@ -24,15 +24,15 @@
 #define GEMTX_CLOCK 1
 #define PRCI_CLOCKS 2
 
-#define MIN_REF 7000000UL
-#define MAX_REF 200000000UL
-#define MAX_PARENT 600000000UL
-#define MAX_VCO 4800000000UL
-#define MAX_DIV 64
-#define MAX_R 64UL
-
-#define PLL_LOCK 0x80000000U
-#define NAME_LEN 40
+#define MIN_REF 7000000ULL
+#define MAX_REF 200000000ULL
+#define MAX_PARENT 600000000ULL
+#define MAX_VCO 4800000000ULL
+#define MAX_DIV 64ULL
+#define MAX_R 64ULL
+
+#define PLL_LOCK 0x80000000ULL
+#define NAME_LEN 40ULL
 
 struct sifive_u54_prci_driver;