OMAP2, 3: DSS2: DSI: create platform_driver, move init, exit to driver

Hwmod adaptation design requires each of the DSS HW IP to be a platform driver.
So a platform_driver for DSI is created and init exit methods are moved from core.c
to its driver probe,remove. pdev member has to be maintained by its own drivers.

Also, vdds_dsi regulator handling is copied to dsi.c, since vdds_dsi regulator is
needed by dpi_init() too. Board files are updated accordingly to add 2 instances of
vdds_dsi regulator.

DSI platform driver is registered from inside omap_dss_probe, in the order desired.

Signed-off-by: Senthilvadivu Guruswamy <svadivu@ti.com>
Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

arch/arm/mach-omap2/board-igep0020.c

@@ -485,8 +485,10 @@ static struct omap_dss_board_info igep2_dss_data = {
 	.default_device	= &igep2_dvi_device,
 };
 
-static struct regulator_consumer_supply igep2_vpll2_supply =
-	REGULATOR_SUPPLY("vdds_dsi", "omapdss");
+static struct regulator_consumer_supply igep2_vpll2_supplies[] = {
+	REGULATOR_SUPPLY("vdds_dsi", "omapdss"),
+	REGULATOR_SUPPLY("vdds_dsi", "omapdss_dsi1"),
+};
 
 static struct regulator_init_data igep2_vpll2 = {
 	.constraints = {
@@ -499,8 +501,8 @@ static struct regulator_init_data igep2_vpll2 = {
 		.valid_ops_mask		= REGULATOR_CHANGE_MODE
 					| REGULATOR_CHANGE_STATUS,
 	},
-	.num_consumer_supplies	= 1,
-	.consumer_supplies	= &igep2_vpll2_supply,
+	.num_consumer_supplies	= ARRAY_SIZE(igep2_vpll2_supplies),
+	.consumer_supplies	= igep2_vpll2_supplies,
 };
 
 static void __init igep2_display_init(void)