System registers that are modified are the Arbiter Configuration
Register (ACR), the System Priority Control Register (SPCR), and the
System Clock Configuration Register (SCCR).

Signed-off by: Michael F. Reiss <Michael.F.Reiss@freescale.com>
Signed-off by: Joe D'Abbraccio <ljd015@freescale.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>