qcacld-3.0: fix code defects for spectral callback registering

Declaring variable spectral_cb without initializer in
sme_register_spectral_cb, spectral_cb.vdev_get_chan_freq_seq2
will be used uninitialized.
To fix it, initialize spectral_cb when declaring.

CRs-Fixed: 2751599
Change-Id: I2c5cd5a85b54dcbda3059bfd528cd18626b6b316

core/sme/src/common/sme_api.c

@@ -1192,7 +1192,7 @@ QDF_STATUS sme_get_valid_channels(uint32_t *ch_freq_list, uint32_t *list_len)
 #ifdef WLAN_CONV_SPECTRAL_ENABLE
 static QDF_STATUS sme_register_spectral_cb(struct mac_context *mac_ctx)
 {
-	struct spectral_legacy_cbacks spectral_cb;
+	struct spectral_legacy_cbacks spectral_cb = {0};
 	QDF_STATUS status;
 
 	spectral_cb.vdev_get_chan_freq = sme_get_oper_chan_freq;