Bluetooth: add WCNSS dependency for HCI driver

The newly added bluetooth driver is based on the soc-specific support,
but lacks the obvious compile-time dependency on that:

drivers/bluetooth/btqcomsmd.o: In function `btqcomsmd_probe':
btqcomsmd.c:(.text.btqcomsmd_probe+0x40): undefined reference to `qcom_wcnss_open_channel'
btqcomsmd.c:(.text.btqcomsmd_probe+0x5c): undefined reference to `qcom_wcnss_open_channel'
Makefile:969: recipe for target 'vmlinux' failed

Fixes: 90c107dc8b2c ("Bluetooth: Introduce Qualcomm WCNSS SMD based HCI driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>