soc: fsl: qe: Remove unnessesary check in ucc_set_tdm_rxtx_clk

Fix smatch warning:

drivers/soc/fsl/qe/ucc.c:526
 ucc_set_tdm_rxtx_clk() warn: unsigned 'tdm_num' is never less than zero.

'tdm_num' is u32 type, never less than zero.
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: Li Yang <leoyang.li@nxp.com>

drivers/soc/fsl/qe/ucc.c

@@ -523,7 +523,7 @@ int ucc_set_tdm_rxtx_clk(u32 tdm_num, enum qe_clock clock,
 
 	qe_mux_reg = &qe_immr->qmx;
 
-	if (tdm_num > 7 || tdm_num < 0)
+	if (tdm_num > 7)
 		return -EINVAL;
 
 	/* The communications direction must be RX or TX */