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>
diff --git a/arch/arm/mach-omap2/clockdomain.c b/arch/arm/mach-omap2/clockdomain.c
index de4278c..b26d30a 100644
--- a/arch/arm/mach-omap2/clockdomain.c
+++ b/arch/arm/mach-omap2/clockdomain.c
@@ -173,6 +173,9 @@
 {
 	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 @@
 {
 	struct clkdm_autodep *autodep;
 
+	if (!autodeps)
+		return;
+
 	for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
 		if (IS_ERR(autodep->clkdm.ptr))
 			continue;