_enable_sysc() and _idle_sysc() handle the midle mode programming correctly
and program HWMOD_IDLEMODE_SMART or HWMOD_IDLEMODE_SMART_WKUP respectively
for supported IPs (The ones which support hardware controlled midle modes)

However the same programming logic is missing when it comes to sidle mode
programming. Here they seem to just set HWMOD_IDLEMODE_SMART (Again for the
ones which support hardware controlled sidle modes)

This problem was hidden due to the fact that a call to _enable_wakeup()
in those same functions would overwrite the idlemodes and program them
correctly (to HWMOD_IDLEMODE_SMART_WKUP in the supported cases)

So fix the sidlemode handling correctly in these functions and handle the
_enable_wakeup() for SIDLEMODE supported IPs same as the way its handled
for MIDLEMODE supported ones.
Tested-by: Vaibhav Bedia <vaibhav.bedia@ti.com>
Tested-by: Sourav Poddar <sourav.poddar@ti.com>
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Tested-by: Kevin Hilman <khilman@linaro.org>  # OMAP4/Panda
Signed-off-by: Paul Walmsley <paul@pwsan.com>