clk: stm32mp1: no more get ck_usbo_48m in device tree

Remove support of ck_usbo_48m clock node in device tree,
but force 48MHz frequency to prepare alignment
with kernel device tree.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/drivers/clk/clk_stm32mp1.c b/drivers/clk/clk_stm32mp1.c
index b7c5d34..88f453c 100644
--- a/drivers/clk/clk_stm32mp1.c
+++ b/drivers/clk/clk_stm32mp1.c
@@ -241,7 +241,6 @@
 	_LSI,
 	_LSE,
 	_I2S_CKIN,
-	_USB_PHY_48,
 	NB_OSC,
 
 /* other parent source */
@@ -273,6 +272,7 @@
 	_CK_MPU,
 	_CK_MCU,
 	_DSI_PHY,
+	_USB_PHY_48,
 	_PARENT_NB,
 	_UNKNOWN_ID = 0xff,
 };
@@ -1079,7 +1079,7 @@
 		break;
 	/* other */
 	case _USB_PHY_48:
-		clock = stm32mp1_clk_get_fixed(priv, _USB_PHY_48);
+		clock = 48000000;
 		break;
 	case _DSI_PHY:
 	{
@@ -1859,7 +1859,7 @@
 		[_HSE] = "clk-hse",
 		[_CSI] = "clk-csi",
 		[_I2S_CKIN] = "i2s_ckin",
-		[_USB_PHY_48] = "ck_usbo_48m"};
+	};
 
 	for (i = 0; i < NB_OSC; i++) {
 		stm32mp1_osc_clk_init(name[i], priv, i);