Honor the environment variable "KBUILD_VERBOSE=1" (as set by make V=1) to
enable verbose mode in scripts/kernel-doc.  Useful for getting more info and
warnings from kernel-doc.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>