scripts/get_maintainer.pl: add --sections, print entire matched subsystem

scripts/get_maintainer.pl: add --sections, print entire matched subsystem

Print the complete contents of the matched subsystems
in pattern match depth order.

Sample output:

$ ./scripts/get_maintainer.pl --sections -f drivers/net/usb/smsc95xx.c
USB SMSC95XX ETHERNET DRIVER
M:Steve Glendinning <steve.glendinning@smsc.com>
L:netdev@vger.kernel.org
S:Supported
F:drivers/net/usb/smsc95xx.*
USB SUBSYSTEM
M:Greg Kroah-Hartman <gregkh@suse.de>
L:linux-usb@vger.kernel.org
W:http://www.linux-usb.org
T:quilt kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/
S:Supported
F:Documentation/usb/
F:drivers/net/usb/
F:drivers/usb/
F:include/linux/usb.h
F:include/linux/usb/
NETWORKING DRIVERS
L:netdev@vger.kernel.org
W:http://www.linuxfoundation.org/en/Net
T:git git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6.git
S:Odd Fixes
F:drivers/net/
F:include/linux/if_*
F:include/linux/*device.h
THE REST
M:Linus Torvalds <torvalds@linux-foundation.org>
L:linux-kernel@vger.kernel.org
Q:http://patchwork.kernel.org/project/LKML/list/
T:git git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
S:Buried alive in reporters
F:*
F:*/

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>