kernel: support for Realtek USB bluetooth devices

USB adaptors with the RTL8761B chipset are cheap and readily available
but so far support is missing in Openwrt.  Enable the relevant kernel
options and add a module to the kmod-bluetooth package.  Increases size
of kmod-bluetooth ipk from 279140 bytes to 285320 bytes on my ath79 build.

Tested on a WNDR3700v4 with rtl8761bu firmware.

Signed-off-by: Quintin Hill <[email protected]>

package/kernel/linux/modules/other.mk

@@ -41,7 +41,7 @@ define KernelPackage/bluetooth
 	CONFIG_BT_HCIBTUSB \
 	CONFIG_BT_HCIBTUSB_BCM=n \
 	CONFIG_BT_HCIBTUSB_MTK=y \
-	CONFIG_BT_HCIBTUSB_RTL=n \
+	CONFIG_BT_HCIBTUSB_RTL=y \
 	CONFIG_BT_HCIUART \
 	CONFIG_BT_HCIUART_BCM=n \
 	CONFIG_BT_HCIUART_INTEL=n \
@@ -56,7 +56,8 @@ define KernelPackage/bluetooth
 	$(LINUX_DIR)/net/bluetooth/hidp/hidp.ko \
 	$(LINUX_DIR)/drivers/bluetooth/hci_uart.ko \
 	$(LINUX_DIR)/drivers/bluetooth/btusb.ko \
-	$(LINUX_DIR)/drivers/bluetooth/btintel.ko
+	$(LINUX_DIR)/drivers/bluetooth/btintel.ko \
+	$(LINUX_DIR)/drivers/bluetooth/btrtl.ko
   AUTOLOAD:=$(call AutoProbe,bluetooth rfcomm bnep hidp hci_uart btusb)
 endef