From: Christoph Hellwig <hch@lst.de>

disk_name() (and hence bdevname()) are now returning devfs-style device names
when devfs is enabled.

This is nice, but these names are very long, and they overflow the 32-char
buffers which these functions use.

The choices are:

a) Use a bigger buffer (increase BDEVNAME_SIZE).

   This might be practical.  But how big?

b) return the name in kmalloced memory, make caller free it up.   Yuk.

c) Add a print_bdevname() thing and intersperse that amongst the printk's.
   This would work.

d) Just print the non-devfs device name.   That's what this patch does.