staging: rtl8712: fix camel case in function r8712_generate_ie

Adhere to linux kernel coding style.

Reported by checkpatch:

CHECK: Avoid CamelCase: <beaconPeriod>
Signed-off-by: Mahak Gupta <mahak_g@cs.iitr.ac.in>
Link: https://lore.kernel.org/r/20220407120945.31030-1-mahak_g@cs.iitr.ac.inSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8712/ieee80211.c

@@ -162,13 +162,13 @@ int r8712_generate_ie(struct registry_priv *registrypriv)
 	uint sz = 0;
 	struct wlan_bssid_ex *dev_network = &registrypriv->dev_network;
 	u8 *ie = dev_network->IEs;
-	u16 beaconPeriod = (u16)dev_network->Configuration.BeaconPeriod;
+	u16 beacon_period = (u16)dev_network->Configuration.BeaconPeriod;
 
 	/*timestamp will be inserted by hardware*/
 	sz += 8;
 	ie += sz;
 	/*beacon interval : 2bytes*/
-	*(__le16 *)ie = cpu_to_le16(beaconPeriod);
+	*(__le16 *)ie = cpu_to_le16(beacon_period);
 	sz += 2;
 	ie += 2;
 	/*capability info*/