OMAP4: DSI: DSI reset removal during enabling

DSI module is made wake up capable in its HWMOD flags but in
The function omapdss_dsi_display_enable(), DSI module is
reset thus values set in DSI_SYSCONFIG is lost because of which
DSI is no longer wakeup capable. This prevents any interrupt from
DSI to be permeated to A9 when A9 sleeping.this reset is not
required while enabling the display thus now it is removed.so it
retains the HWMOD settings.

Now with this fix, the mdelay() within dsi_vc_send_bta_sync(), is removed
and a proper interrupt based implementation is done.

Change-Id: If6c3d25a5ba8003a0bd7732af0fcd81a839293aa
Signed-off-by: Sujeet Kumar Baranwal <s-baranwal@ti.com>

Conflicts:
	drivers/video/omap2/dss/dsi.c