ARM: 7003/1: vexpress: Add clock definition for the SP805.

It seems that an entry for the SP805 watchdog in the table of clocks was
missing.  This results in the sp805_wdt driver rejecting the device with
the following errors:

  sp805-wdt mb:wdt: Clock not found
  sp805-wdt mb:wdt: Probe Failed!!!
  sp805-wdt: probe of mb:wdt failed with error -2

While not obviously stated in the hardware docs, the onboard SP810's
"REFCLK" is connected to a 32.768KHz crystal, and this drives the
watchdog.  Add a struct clk and corresponding lookup entry for it.
Signed-off-by: Nick Bowler <nbowler@elliptictech.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-vexpress/v2m.c

@@ -318,6 +318,10 @@ static struct clk v2m_sp804_clk = {
 	.rate	= 1000000,
 };
 
+static struct clk v2m_ref_clk = {
+	.rate   = 32768,
+};
+
 static struct clk dummy_apb_pclk;
 
 static struct clk_lookup v2m_lookups[] = {
@@ -348,6 +352,9 @@ static struct clk_lookup v2m_lookups[] = {
 	}, {	/* CLCD */
 		.dev_id		= "mb:clcd",
 		.clk		= &osc1_clk,
+	}, {	/* SP805 WDT */
+		.dev_id		= "mb:wdt",
+		.clk		= &v2m_ref_clk,
 	}, {	/* SP804 timers */
 		.dev_id		= "sp804",
 		.con_id		= "v2m-timer0",