Convert private ABS() defines and callers to use abs() from linux/kernel.h.
 Builds successfully.  stv0299, riva, & sstfb modules load.
Signed-off-by: Randy Dunlap <rddunlap@osdl.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>