MX5: Add initial support for MX53 processor

Add initial support for Freescale MX53 processor,

- Add the iomux support and the pin definition,
- Add the regs definition, clean up some unused def from mx51,
- Add the low level init support, make use the freq input of setup_pll macro

Signed-off-by: Jason Liu  <r64343@freescale.com>
9 files changed