omap4: hwmod_data: add clocks to ipu processor devices

The ipu processor hwmod devices (ipu_c0 & ipu_c1) are defined
primarily as pseudo-hwmod devices with only reset controls.
These share the same functional clock along with the ipu hwmod
device that is mainly used for controlling the MMU. This clock
name is added to these pseudo-hwmod devices, as it will improve
the robustness to any HW_AUTO settings performed within the
hwmod framework. There is no major effect on the clock framework
itself, as the clock enable & disable will simply be reference
counted and the functionality would be identical as before.

Change-Id: I865e9690b503e601df27aa0a55cfac45622c4259
Signed-off-by: Suman Anna <s-anna@ti.com>