stm32mp1: update clock driver

Remove useless private structure in function prototypes.
Add a reference counter on clocks.
Prepare for future secured/shared/non-secured clocks.

Change-Id: I3dbed81721da5ceff5e10b2c4155b1e340c036ee
Signed-off-by: Yann Gautier <yann.gautier@st.com>
Signed-off-by: Etienne Carriere <etienne.carriere@st.com>
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Signed-off-by: Nicolas LE BAYON <nicolas.le.bayon@st.com>
diff --git a/drivers/st/mmc/stm32_sdmmc2.c b/drivers/st/mmc/stm32_sdmmc2.c
index 017dd88..06de112 100644
--- a/drivers/st/mmc/stm32_sdmmc2.c
+++ b/drivers/st/mmc/stm32_sdmmc2.c
@@ -702,8 +702,6 @@
 
 int stm32_sdmmc2_mmc_init(struct stm32_sdmmc2_params *params)
 {
-	int ret;
-
 	assert((params != NULL) &&
 	       ((params->reg_base & MMC_BLOCK_MASK) == 0U) &&
 	       ((params->bus_width == MMC_BUS_WIDTH_1) ||
@@ -717,12 +715,7 @@
 		return -ENOMEM;
 	}
 
-	ret = stm32mp_clk_enable(sdmmc2_params.clock_id);
-	if (ret != 0) {
-		ERROR("%s: clock %d failed\n", __func__,
-		      sdmmc2_params.clock_id);
-		return ret;
-	}
+	stm32mp_clk_enable(sdmmc2_params.clock_id);
 
 	stm32mp_reset_assert(sdmmc2_params.reset_id);
 	udelay(2);