OMAP clock: drop .id field; ensure each clock has a unique name

OMAP clock: drop .id field; ensure each clock has a unique name

After the clkdev conversion, the struct clk.id field became
superfluous, so, drop it.  Bring the clock names closer to the TRMs
and ensure they are unique for debugfs.

Signed-off-by: Paul Walmsley <paul@pwsan.com>