syscalls/mount/mount02.c: cleanup

1. Remove redundant comments

2. Revise code to follow ltp-code-style

Signed-off-by: DAN LI <li.dan@cn.fujitsu.com>
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
syscalls/mount/mount02.c: modify array "exp_enos"

Expected errno setted in array "exp_enos" do not match
echo test item rightly, leading to two problems:

* Not every test item in mount02 is executed.
     There are 13 test items in mount02 currently to test error:
     ENODEV, ENOTBLK, EBUSY, EBUSY, EINVAL, EINVAL, EINVAL, EFAULT,
     EFAULT, ENAMETOOLONG, ENOENT, ENOENT, ENOTDIR

     But, only 8 of them are tested as specified in array "exp_enos":
     ENODEV, ENOTBLK, EBUSY, EINVAL, EFAULT, ENAMETOOLONG,
     ENOENT, ENOTDIR

* For test item which is executed, its errno returned is maybe not
the one expected.

This patch modifies array "exp_enos" to make it one-to-one correspondent
with each test item, to fix above problems.

Signed-off-by: DAN LI <li.dan@cn.fujitsu.com>
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>