kernel: backport bcma init patch from 4.5

This simply replaces init fix with a final version and puts it in a
generic dir. This will allow backporting some trivial changes from 4.6.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

git-svn-id: svn://svn.openwrt.org/openwrt/branches/chaos_calmer@48788 3c298f89-4303-0410-b956-a3cf2f4a3e73

target/linux/generic/patches-3.18/031-bcma-from-4.5.patch

@@ -0,0 +1,49 @@
+--- a/drivers/bcma/main.c
++++ b/drivers/bcma/main.c
+@@ -637,11 +637,36 @@ static int bcma_device_uevent(struct dev
+ 			      core->id.rev, core->id.class);
+ }
+ 
+-static int __init bcma_modinit(void)
++static unsigned int bcma_bus_registered;
++
++/*
++ * If built-in, bus has to be registered early, before any driver calls
++ * bcma_driver_register.
++ * Otherwise registering driver would trigger BUG in driver_register.
++ */
++static int __init bcma_init_bus_register(void)
+ {
+ 	int err;
+ 
++	if (bcma_bus_registered)
++		return 0;
++
+ 	err = bus_register(&bcma_bus_type);
++	if (!err)
++		bcma_bus_registered = 1;
++
++	return err;
++}
++#ifndef MODULE
++fs_initcall(bcma_init_bus_register);
++#endif
++
++/* Main initialization has to be done with SPI/mtd/NAND/SPROM available */
++static int __init bcma_modinit(void)
++{
++	int err;
++
++	err = bcma_init_bus_register();
+ 	if (err)
+ 		return err;
+ 
+@@ -660,7 +685,7 @@ static int __init bcma_modinit(void)
+ 
+ 	return err;
+ }
+-fs_initcall(bcma_modinit);
++module_init(bcma_modinit);
+ 
+ static void __exit bcma_modexit(void)
+ {