linux-phytec-ti

ARM: i.MX21 clk: Cleanup driver

This is a cleanup for i.MX21 clk driver. This change includes:
- Reduce license text.
- Remove unused definitions.
- Remove unused #include and sort the rest.
- Remove useless comment.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>