works now with 48 MHz Clock, but range needs to be manually set to 1 in cpu.c:
  /* MCG_C10: LOCRE2=0,??=0,RANGE1=2,HGO1=0,EREFS1=1,??=0,??=0 */
  MCG_C10 = (MCG_C10_RANGE1(0x01) | MCG_C10_EREFS1_MASK);
  /* MCG_C2: LOCRE0=0,??=0,RANGE0=2,HGO0=0,EREFS0=0,LP=0,IRCS=0 */
  MCG_C2 = MCG_C2_RANGE0(0x01);
added USB stack, but interrupts do not fire yet?
added USB CDC project for TWR-MCF52259