encoding: fix gen_freq_params(): do not check pdch twice

This is a left-over from an earlier version of [1] that makes
Coverity think that there can be NULL pointer dereference,
even despite we assert(pdch != NULL).

[1] I8adc0cdb1b05a87b4df5d4bc196f6d381283a06f

Change-Id: I3490c38e0c1186dfd2fae63526a05c694547cebb
Fixes: CID#214230

src/encoding.cpp

@@ -565,7 +565,7 @@ static void gen_freq_params(Frequency_Parameters_t *freq_params,
 	freq_params->TSC = pdch->tsc;
 
 	/* If frequency hopping is not in use, encode a single ARFCN */
-	if (pdch == NULL || !pdch->fh.enabled) {
+	if (!pdch->fh.enabled) {
 		freq_params->UnionType = 0x00;
 		freq_params->u.ARFCN = tbf->trx->arfcn;
 		return;