staging: tidspbridge: detect wdt3 feature at runtime

In order to detect WDT feature on the dsp code, we need to
find the symbol used to enable it inside the baseimage.

This should fix the warning comming from L3 driver:

    WARNING: at arch/arm/mach-omap2/omap_l3_smx.c:161 omap3_l3_app_irq...
    In-band Error seen by IVA_SS  at address 0
    ...

That occurs because the dsp tries to access wdt3 registers when the clock
for those registers is not enabled.
Reported-by: NFelipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: NOmar Ramirez Luna <omar.ramirez@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/tidspbridge/core/tiomap3430.c

@@ -383,6 +383,7 @@ static int bridge_brd_start(struct bridge_dev_context *dev_ctxt,
 	u32 clk_cmd;
 	struct io_mgr *hio_mgr;
 	u32 ul_load_monitor_timer;
+	u32 wdt_en = 0;
 	struct omap_dsp_platform_data *pdata =
 		omap_dspbridge_dev->dev.platform_data;
 
@@ -594,9 +595,12 @@ static int bridge_brd_start(struct bridge_dev_context *dev_ctxt,
 		if (!wait_for_start(dev_context, dw_sync_addr))
 			status = -ETIMEDOUT;
 
+		dev_get_symbol(dev_context->dev_obj, "_WDT_enable", &wdt_en);
+		if (wdt_en) {
 			/* Start wdt */
 			dsp_wdt_sm_set((void *)ul_shm_base);
 			dsp_wdt_enable(true);
+		}
 
 		status = dev_get_io_mgr(dev_context->dev_obj, &hio_mgr);
 		if (hio_mgr) {