OMAP clockdomain: if no autodeps exist, don't try to add or remove them

_clkdm_add_autodeps() and _clkdm_del_autodeps() will attempt to dereference
a NULL pointer if no autodeps were supplied to clkdm_init().

Based on a patch from Roel Kluin <roel.kluin@gmail.com> - thanks Roel.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Roel Kluin <roel.kluin@gmail.com>

arch/arm/mach-omap2/clockdomain.c

@@ -173,6 +173,9 @@ static void _clkdm_add_autodeps(struct clockdomain *clkdm)
 {
 	struct clkdm_autodep *autodep;
 
+	if (!autodeps)
+		return;
+
 	for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
 		if (IS_ERR(autodep->clkdm.ptr))
 			continue;
@@ -201,6 +204,9 @@ static void _clkdm_del_autodeps(struct clockdomain *clkdm)
 {
 	struct clkdm_autodep *autodep;
 
+	if (!autodeps)
+		return;
+
 	for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
 		if (IS_ERR(autodep->clkdm.ptr))
 			continue;