Merge pull request arduino#174 from nekuneko/patch-2

Enable TC6 & TC7 for __SAMD21J18A__

Author: ladyada

cores/arduino/wiring.c

@@ -92,7 +92,7 @@ void init( void )
   PM->APBCMASK.reg |= PM_APBCMASK_SERCOM0 | PM_APBCMASK_SERCOM1 | PM_APBCMASK_SERCOM2 | PM_APBCMASK_SERCOM3 | PM_APBCMASK_SERCOM4 | PM_APBCMASK_SERCOM5 ;
 
   // Clock TC/TCC for Pulse and Analog
-  PM->APBCMASK.reg |= PM_APBCMASK_TCC0 | PM_APBCMASK_TCC1 | PM_APBCMASK_TCC2 | PM_APBCMASK_TC3 | PM_APBCMASK_TC4 | PM_APBCMASK_TC5 ;
+  PM->APBCMASK.reg |= PM_APBCMASK_TCC0 | PM_APBCMASK_TCC1 | PM_APBCMASK_TCC2 | PM_APBCMASK_TC3 | PM_APBCMASK_TC4 | PM_APBCMASK_TC5 |= PM_APBCMASK_TC6 | PM_APBCMASK_TC7;
 
   // ATSAMR, for example, doesn't have a DAC
   #ifdef PM_APBCMASK_DAC