Add register bit defs for DAC & PDB DAC trigger

teensy3/kinetis.h

 #define DAC0_DAT14L		(*(volatile uint8_t  *)0x400CC01C) // DAC Data Low Register
 #define DAC0_DAT15L		(*(volatile uint8_t  *)0x400CC01E) // DAC Data Low Register
 #define DAC0_SR			(*(volatile uint8_t  *)0x400CC020) // DAC Status Register
+#define DAC_SR_DACBFWMF			0x04				// Buffer Watermark Flag
+#define DAC_SR_DACBFRTF			0x02				// Pointer Top Position Flag
+#define DAC_SR_DACBFRBF			0x01				// Pointer Bottom Position Flag
 #define DAC0_C0			(*(volatile uint8_t  *)0x400CC021) // DAC Control Register
 #define DAC_C0_DACEN			0x80				// DAC Enable
 #define DAC_C0_DACRFS			0x40				// DAC Reference Select
 #define PDB0_CH1DLY0		(*(volatile uint32_t *)0x40036040) // Channel 1 Delay 0 Register
 #define PDB0_CH1DLY1		(*(volatile uint32_t *)0x40036044) // Channel 1 Delay 1 Register
 #define PDB0_DACINTC0		(*(volatile uint32_t *)0x40036150) // DAC Interval Trigger n Control Register
+#define PDB_DACINTC_EXT			0x02			// External Trigger Input Enable
+#define PDB_DACINTC_TOE			0x01			// Interval Trigger Enable
 #define PDB0_DACINT0		(*(volatile uint32_t *)0x40036154) // DAC Interval n Register
 #define PDB0_DACINTC1		(*(volatile uint32_t *)0x40036158) // DAC Interval Trigger n Control register
 #define PDB0_DACINT1		(*(volatile uint32_t *)0x4003615C) // DAC Interval n register