isa: Call isa_bus_init before dependent ISA bus drivers register

BugLink: https://bugs.launchpad.net/bugs/1878232

commit 32a5a0c0 upstream.

The isa_bus_init function must be called before drivers which utilize
the ISA bus driver are registered. A race condition for initilization
exists if device_initcall is used (the isa_bus_init callback is placed
in the same initcall level as dependent drivers which use module_init).
This patch ensures that isa_bus_init is called first by utilizing
postcore_initcall in favor of device_initcall.

Fixes: a5117ba7 ("[PATCH] Driver model: add ISA bus")
Cc: Rene Herman <rene.herman@keyaccess.nl>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/base/isa.c

@@ -180,4 +180,4 @@ static int __init isa_bus_init(void)
 	return error;
 }
 
-device_initcall(isa_bus_init);
+postcore_initcall(isa_bus_init);