dcd_synopsys.c included broadcom/interrupts.h before
preprocessor check whether file should be used.
Since mynewt build does not include all folders it resulted in build
error.
Now offending include is moved few lines after preprocessor check.
dcd_da1469x can work with broader range of MCUs that
share same USB core.
Specific header file that was used DA1469xAB.h now it is changed
to mcu/mcu.h which includes actual MCU specific register file.
Jerzy Kasenberg