ddr: altera: Clean up initialize_reg_file()

Add brief kerneldoc.

Signed-off-by: Marek Vasut <marex@denx.de>
diff --git a/drivers/ddr/altera/sequencer.c b/drivers/ddr/altera/sequencer.c
index 7907b63..72b2021 100644
--- a/drivers/ddr/altera/sequencer.c
+++ b/drivers/ddr/altera/sequencer.c
@@ -3630,6 +3630,11 @@
 		writel(ac_rom_init[i], addr + (i << 2));
 }
 
+/**
+ * initialize_reg_file() - Initialize SDR register file
+ *
+ * Initialize SDR register file.
+ */
 static void initialize_reg_file(void)
 {
 	/* Initialize the register file with the correct data */