OMAP4: hwmod data: Add clock domain attribute

In OMAP PRCM terminology, the clock domain is defined as a group of IPs
that share some clocks and most of the time an interface clock.
Every IP does belong to a clockdomain.
For the moment the clock domain attribute is affected to a clock node.
The issue with that approach, is that a clock might or not belong to a
clock domain. Moreover during module transition, it is up to a module
to handle properly the clock domain state and not to a clock node.

Create a clkdm_name attribute to provide this information per hwmod.

Populate this attribute for every OMAP4 hwmod entries.

Future cleanup series with remove that information from the OMAP4 clock
when it is relevant.

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Rajendra Nayak <rnayak@ti.com>
[paul@pwsan.com: fix the mpuss_clkdm name]
Signed-off-by: Paul Walmsley <paul@pwsan.com>