bsps/cadence-spi: Fix moduleid offset

Move the moduleid register to the correct offset according to Cadence IP
documentation.

bsps/include/dev/spi/cadence-spi-regs.h

@@ -78,6 +78,7 @@ typedef struct {
 	uint32_t slave_idle_count;
 	uint32_t txthreshold;
 	uint32_t rxthreshold;
+	uint32_t unused[51];
 	uint32_t moduleid;
 } cadence_spi;