ARM: OMAP4: hwmod data: add OCP_USER_DSP; mark omap44xx_dsp__iva appropriately

One of the OMAP4 links was missing OCP_USER flags, since it was only
used by the DSP initiator, and we did not have an OCP_USER_DSP flag.
Future patches will switch the hwmod code and data to register
interfaces, rather than hwmods, and it will be mandatory for all
interfaces to have at least one user bit set.  This patch resolves the
issue by adding OCP_USER_DSP and marking the DSP-IVA interface
appropriately.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoît Cousson <b-cousson@ti.com>