[PATCH] Change dash2underscore() return value to char

[PATCH] Change dash2underscore() return value to char

Since dash2underscore() just operates and returns chars, I guess its safe
to change the return value to a char.  With my .config, this reduces its
size by 5 bytes.

   text    data     bss     dec     hex filename
   4155     152       0    4307    10d3 params.o.orig
   4150     152       0    4302    10ce params.o

Signed-off-by: Eric Sesterhenn <[email protected]>
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Adrian Bunk <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>