clk: at91: utmi: add timeout for utmi lock

In case the slow clock is not properly configured, the UTMI clock
cannot lock the PLL, because UPLLCOUNT will "wait X slow clock cycles".
In this case U-boot will loop indefinitely.
Added a timeout in this case, to start U-boot even if UTMI clock is
not enabled, so the user can use different media if needed, or investigate.
Signed-off-by: NEugen Hristev <eugen.hristev@microchip.com>

drivers/clk/at91/clk-utmi.c

@@ -28,6 +28,7 @@ static int utmi_clk_enable(struct clk *clk)
 	u32 utmi_ref_clk_freq;
 	u32 tmp;
 	int err;
+	int timeout = 2000000;
 
 	if (readl(&pmc->sr) & AT91_PMC_LOCKU)
 		return 0;
@@ -85,8 +86,12 @@ static int utmi_clk_enable(struct clk *clk)
 	       AT91_PMC_BIASEN;
 	writel(tmp, &pmc->uckr);
 
-	while (!(readl(&pmc->sr) & AT91_PMC_LOCKU))
+	while ((--timeout) && !(readl(&pmc->sr) & AT91_PMC_LOCKU))
 		;
+	if (!timeout) {
+		printf("UTMICK: timeout waiting for UPLL lock\n");
+		return -ETIMEDOUT;
+	}
 
 	return 0;
 }