[PATCH] add clock debug information for imx51 babbage

[Yong Shen]

Hi there,

This patch makes BSP development easier, since it displays the whole
clock information in tree-like manner. The final goal is to make it a
part of common clock framework, but so far this goal depends on other
unfinished work.

PS: Due to the firewall problem, I send out patch this way. Please
give comments inline and use attached patch for testing.