OMAP UART IP needs software control for slave idle modes based on functional
state of the IP. i.e The IP slave idle settings should be set to 'noidle' when
being used and then put back to 'smart_idle' when unused. Currently this is
handled by the driver with function pointers implemented in platform code.
This however breaks in case of device tree because of missing idle handling
APIs.

Previous patches in this series added a flag HWMOD_SWSUP_SIDLE_ACTIVE which
takes care of the mentioned requirement. Hence add the flag for all UART IPs
to take advantage of feature supported by framework.

Subsequent patches removes the slave idle handling from driver code.
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>