clkout2 comes out on the pad and is being used by various
external on-board peripherals like, Audio codecs and stuff.
So enable the clkout2 by default during init sequence itself.

Also, add the missing entry of "clkout2_ck" to the clock table.
Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Benoit Cousson <benoit.cousson@linaro.org>