Add register definitions for the i.MX23 power control block and
clock control block. These are essential for the basic bootstrap
of the i.MX23. Also, properly include them in imx-regs.h .

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Otavio Salvador <otavio@ossystems.com.br>
Cc: Stefano Babic <sbabic@denx.de>