makedevs: several fixes

makedevs: several fixes

This patch fixes below issues:

1. In makedevs.c file, it lost related functions definition about "-q" and
"--squash" options. So we should remove help information of these options
from makedevs.c to fix this issue.

2. Previously, It returned nothing when makedevs command be executed with
none or invalid option. We hope to print help information and return non-zero
value.

3. If use '-d' option to pick non-existent dir, error messages should be returned.

(From OE-Core rev: 24089364c3d11665c9ac3210c1fa2488017b6b73)

Signed-off-by: Lu Chong <Chong.Lu@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>