Small cleanup of device name routines

[Marin Ramesa]

What follows is a small cleanup of device name routines. Patches
2, 4 and 7 can be applied at the same time. They are just changes
in style for consistency. I didn't know how to combine them in one 
commit, so I'm sending them this way, I hope this is not a problem.
I'm not sure about patch 3 - I added checking for null-termination
in name_equal() - this prevents pointers from going to addresses
beyond null-termination, but I am not sure if this is a problem that
requires a modification, if it's a problem at all.

[PATCH 1/7] remove register qualifiers
[PATCH 2/7] small style changes for consistency
[PATCH 3/7] name_equal: return early from function if src null-terminates in 
the loop
[PATCH 4/7] another small change in style for consistency
[PATCH 5/7] remove preprocessor comments
[PATCH 6/7] use boolean_t instead of an int
[PATCH 7/7] another small change in style for consistency