OMAP: omap_device: Create clkdev entry for hwmod main_clk

OMAP: omap_device: Create clkdev entry for hwmod main_clk

Extend the existing function to create clkdev for every optional
clocks to add a well one "fck" alias for the main_clk of the
omap_hwmod.
It will allow to remove these static clkdev entries from the
clockXXX_data.c file.

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Todd Poynor <toddpoynor@google.com>
[paul@pwsan.com: remove all of the "fck" role clkdev aliases from the
 clock data files; fixed error message]
Signed-off-by: Paul Walmsley <paul@pwsan.com>