init/do_mounts.c: add create_dev() failure log

init/do_mounts.c: add create_dev() failure log

If create_dev() function fails to create the root mount device
(/dev/root), then it goes to panic as root device not found but there is
no printk in this case.  So I have added the log in case it fails to
create the root device.  It will help in debugging.

[[email protected]: simplify printk(), use pr_emerg(), display errno]
Signed-off-by: Vishnu Pratap Singh <[email protected]>
Acked-by: Pavel Machek <[email protected]>
Cc: Paul Gortmaker <[email protected]>
Cc: Mike Snitzer <[email protected]>
Cc: Dan Ehrenberg <[email protected]>
Cc: Miklos Szeredi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>