ARM: OMAP2+: hwmod: Invoke init_clkdm before other init functions

Without this kernel would crash, since clkdm inside omap_hwmod
is accessed in some of the init functions like, _init_main_clk.

So call init_clkdm before _init_main_clk().

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Mike Turquette <mturquette@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>