APPLY needs to know at certain places whether an overlay manager is in manual
or auto update mode. The caps of the connected omap_dss_device were used to
check that.

A LCD manager is in manual update if stallmode is enabled for that manager. TV
managers for now always auto update.

Return the value of stallmode parameter in the private data 'lcd_confg' in
mgr_manual_update() and ovl_manual_update(), for TV managers stallmode field
will be false by default.
Signed-off-by: NArchit Taneja <archit@ti.com>