cmfs: add missing masklog item into fs/cmfs/Makefile

Previous cmfs/0002-cmfs-mask-log.patch did not add masklog.o item into
fs/cmfs/Makefile, this commit adds masklog.o into cmfs-objs items.
cmfs: solve a merge conflict in fs/cmfs/Makefile

Last commit to cmfs/0002-cmfs-mask-log.patch adds masklog.o into
cmfs-objs, which introduces confliction when applying
cmfs/0003-cmfs-basic-mount-implementation.patch.

This commit fixes the confliction in fs/cmfs/Makefile.
cmfs: fix several errors to cmfs/0004-cmfs-basic-jbd2-journal-support.patch

This commit includes several fixes to
cmfs/0004-cmfs-basic-jbd2-journal-support.patch,

1) errors reported by scripts/checkpatch.pl
2) remove garbage part of cmfs.mod.c
3) remove garbage part of *.ko
4) add extern declaration of cmfs_wq in fs/cmfs/cmfs_fs.h
cmfs: add module_init(), module_exit() and other depended routines

This patch adds module_init() and module_exit() to cmfs code. Now cmfs.ko is able to be executed in mount.

module_init()/exit() reference cmfs_init()/exit(), this patch also adds other routines which are necessary by cmfs_init() and cmfs_exit().

Currently the code just passes gcc compiling, there are several stub routines needs to be implemented.