msm: camera: common: Make platform register centralized

Currently camera modules platform registration/remove function
is being called as a part of module_init function individually.
Building camera as module, current infrastructure cannot support
it, as DLKM only support single module_init/exit function.
This change enables that support by combining all platform
entry/remove functions centrally. Also, remove all submodule
makefiles and combined into one root makefile in order to generate
single kernel object file to dynamically loading the kernel module
in case of DLKM compilation.

CRs-Fixed: 2569808
Change-Id: I59db3ed6cef60123e474db2f222c39836056bd6e
Signed-off-by: Jigarkumar Zala <jzala@codeaurora.org>
Signed-off-by: Karthik Jayakumar <kjayakum@codeaurora.org>

drivers/cam_icp/cam_icp_subdev.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2017-2019, The Linux Foundation. All rights reserved.
  */
 
 #include <linux/delay.h>
@@ -260,16 +260,15 @@ static struct platform_driver cam_icp_driver = {
 	},
 };
 
-static int __init cam_icp_init_module(void)
+int cam_icp_init_module(void)
 {
 	return platform_driver_register(&cam_icp_driver);
 }
 
-static void __exit cam_icp_exit_module(void)
+void cam_icp_exit_module(void)
 {
 	platform_driver_unregister(&cam_icp_driver);
 }
-module_init(cam_icp_init_module);
-module_exit(cam_icp_exit_module);
+
 MODULE_DESCRIPTION("MSM ICP driver");
 MODULE_LICENSE("GPL v2");