omapdss: HDMI: create a Wrapper library

omapdss: HDMI: create a Wrapper library

HDMI wrapper is a block common to DSS in OMAP4, OMAP5 and DRA7x. Move the
existing functions from ti_hdmi_4xxx_ip.c to a separate file. These funcs are
called directly from the hdmi driver rather than hdmi_ip_ops funtion pointer
calls.

Add new wrapper funcs which can be used by other hdmi libraries like core, pll
and phy. Move some of the enums, structs and funcs related to the wrapper from
ti_hdmi_4xxx_ip.h to ti_hdmi.h. These will be shared amongst the omap4/5 hdmi
platform drivers and other libraries.

The old hdmi_wp_init() is removed since it didn't do anything. Timing parameters
like interlace, hsync_level and vsync_level weren't copied correctly before.
Those are copied correctly now.

The DT/hwmod information for hdmi doesn't split the address space according to
the required sub blocks. Keep the address offset and size information in the
driver for now. This will be removed when the driver gets the information
correctly from DT/hwmod.

Signed-off-by: Archit Taneja <archit@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>