[ARM] omap: create a proper tree of clocks

Traditionally, we've tracked the parent/child relationships between
clk structures by setting the child's parent member to point at the
upstream clock.  As a result, when decending the tree, we have had
to scan all clocks to find the children.

Avoid this wasteful scanning by keeping a list of the clock's children.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c
index 478ca66..38a7898 100644
--- a/arch/arm/mach-omap2/clock.c
+++ b/arch/arm/mach-omap2/clock.c
@@ -175,7 +175,7 @@
 						 clk->name, clks->parent->name,
 						 ((clk->parent) ?
 						  clk->parent->name : "NULL"));
-					clk->parent = clks->parent;
+					clk_reparent(clk, clks->parent);
 				};
 				found = 1;
 			}
@@ -780,7 +780,7 @@
 	if (clk->usecount > 0)
 		_omap2_clk_enable(clk);
 
-	clk->parent = new_parent;
+	clk_reparent(clk, new_parent);
 
 	/* CLKSEL clocks follow their parents' rates, divided by a divisor */
 	clk->rate = new_parent->rate;