qcacld-3.0: Load driver on late initcall when not built as a module

Requiring userspace to write to /sys/kernel/boot_wlan/boot_wlan to boot
up the wlan device is unnecessary and blocks userspace for the large
amount of time it takes for wlan boot to finish.

Instead, load the driver asynchronously on late_initcall.

Change-Id: I4d696b9d46de032158fd223c60d9a7dbde26cc3f
Signed-off-by: Sultanxda <sultanxda@gmail.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Akhil Narang <akhilnarang.1999@gmail.com>
[luca.weiss@fairphone.com: adjust for 4.19]
Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>