fix: remove useless "return" at void functions

void functions() returns nothing. So remove useless "return".

found using checkpatch.pl[1]

[1]: https://review.coreboot.org/plugins/gitiles/coreboot/+/refs/heads/master/util/lint/checkpatch.pl

Change-Id: I3daab2abec225a657af48f7d8c215cc554713074
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>

drivers/arm/css/mhu/css_mhu_doorbell.c

@@ -15,7 +15,6 @@ void mhu_ring_doorbell(struct scmi_channel_plat_info *plat_info)
 	MHU_RING_DOORBELL(plat_info->db_reg_addr,
 			plat_info->db_modify_mask,
 			plat_info->db_preserve_mask);
-	return;
 }
 
 void mhuv2_ring_doorbell(struct scmi_channel_plat_info *plat_info)
@@ -35,6 +34,4 @@ void mhuv2_ring_doorbell(struct scmi_channel_plat_info *plat_info)
 
 	/* clear the access request for the receiver */
 	MHU_V2_CLEAR_REQUEST(mhuv2_base);
-
-	return;
 }

plat/imx/common/sci/svc/pm/pm_rpc_clnt.c

@@ -412,8 +412,6 @@ void sc_pm_reboot(sc_ipc_t ipc, sc_pm_reset_type_t type)
 	RPC_SIZE(&msg) = 2U;
 
 	sc_call_rpc(ipc, &msg, SC_TRUE);
-
-	return;
 }
 
 sc_err_t sc_pm_reboot_partition(sc_ipc_t ipc, sc_rm_pt_t pt,

plat/imx/common/sci/svc/rm/rm_rpc_clnt.c

@@ -632,8 +632,6 @@ void sc_rm_dump(sc_ipc_t ipc)
 	RPC_SIZE(&msg) = 1U;
 
 	sc_call_rpc(ipc, &msg, SC_FALSE);
-
-	return;
 }
 
 /**@}*/

plat/nvidia/tegra/soc/t194/plat_ras.c

@@ -249,7 +249,6 @@ void tegra194_ras_corrected_err_clear(uint64_t *cookie)
 	 * of range.
 	 */
 	*cookie = 0ULL;
-	return;
 }
 
 /* Function to probe an error from error record group. */