clk: agilex: Add clock enable support

Some drivers probing failed if clock enable function is not supported in
clock driver. So, add clock enable function to clock driver to solve it.

Return 0 (success) for *.enable function because all clocks are enabled
by default in clock driver probe.

Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
Signed-off-by: Chee Hong Ang <chee.hong.ang@intel.com>
diff --git a/drivers/clk/altera/clk-agilex.c b/drivers/clk/altera/clk-agilex.c
index d740299..36a224d 100644
--- a/drivers/clk/altera/clk-agilex.c
+++ b/drivers/clk/altera/clk-agilex.c
@@ -542,6 +542,11 @@
 	}
 }
 
+static int socfpga_clk_enable(struct clk *clk)
+{
+	return 0;
+}
+
 static int socfpga_clk_probe(struct udevice *dev)
 {
 	const struct cm_config *cm_default_cfg = cm_get_default_config();
@@ -565,6 +570,7 @@
 }
 
 static struct clk_ops socfpga_clk_ops = {
+	.enable		= socfpga_clk_enable,
 	.get_rate	= socfpga_clk_get_rate,
 };