drivers/adxl345: Changes INT1/2 to INT1_ACC
drivers/adxl345: Changes INT1/2 to INT1_ACC

INT1 is already defined by avr/io.h for all Atmel MCUs. The namechange allows usage of the driver

Josar/RIOT,Josar/RIOT,Josar/RIOT,Josar/RIOT,Josar/RIOT