ARM: OMAP2+: hwmod code: convert missing clockdomain warnings to debug messages

The decision was made a few months ago to allow struct omap_hwmod
records and struct clk records to omit clockdomain information if the
clockdomain is not software-controllable.  See for example commit
868c157d ("ARM: OMAP2+: hwmod: remove
prm_clkdm, cm_clkdm; allow hwmods to have no clockdomain").

So convert an existing pr_warning() to a pr_debug() (regarding missing
clockdomains in clocks), and add a pr_debug() for missing hwmod
clockdomains.  It's still useful to enable these messages for
debugging, since missing clockdomains can cause hard-to-debug problems
with power management; see for example commit
6c4a057b ("ARM: OMAP4: clock data:
Force a DPLL clkdm/pwrdm ON before a relock").
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoît Cousson <b-cousson@ti.com>

arch/arm/mach-omap2/omap_hwmod.c

@@ -696,7 +696,7 @@ static int _init_main_clk(struct omap_hwmod *oh)
 	clk_prepare(oh->_clk);
 
 	if (!oh->_clk->clkdm)
-		pr_warning("omap_hwmod: %s: missing clockdomain for %s.\n",
+		pr_debug("omap_hwmod: %s: missing clockdomain for %s.\n",
 			   oh->name, oh->main_clk);
 
 	return ret;
@@ -1454,8 +1454,10 @@ static struct omap_hwmod *_lookup(const char *name)
  */
 static int _init_clkdm(struct omap_hwmod *oh)
 {
-	if (!oh->clkdm_name)
+	if (!oh->clkdm_name) {
+		pr_debug("omap_hwmod: %s: missing clockdomain\n", oh->name);
 		return 0;
+	}
 
 	oh->clkdm = clkdm_lookup(oh->clkdm_name);
 	if (!oh->clkdm) {