With the OMAP serial driver sysc cleanup patches in this series, we can
now remove the hwmod external apis for sysc fiddling.

While at this, also remove unused sysc auto idle api from hwmod code.
Tested-by: NVaibhav Bedia <vaibhav.bedia@ti.com>
Tested-by: NSourav Poddar <sourav.poddar@ti.com>
Signed-off-by: NRajendra nayak <rnayak@ti.com>
Signed-off-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: NKevin Hilman <khilman@linaro.org>
Tested-by: Kevin Hilman <khilman@linaro.org>  # OMAP4/Panda
Signed-off-by: NPaul Walmsley <paul@pwsan.com>