genirq: Add kerneldoc for irq_disable.
genirq: Add kerneldoc for irq_disable.

Document the lazy disable functionality. comment based on changelog of
d209a699a0b975ad

Signed-off-by: Andreas Fenkart <5956c1053cc7d77d3ae9490c27bdb39cfb984101@streamunlimited.com>
Cc: 94dddeeef08b001e003cce128ddc162a4e2c6cd2@ti.com
Link: http://lkml.kernel.org/r/1368181290-1583-1-git-send-email-5956c1053cc7d77d3ae9490c27bdb39cfb984101@streamunlimited.com
Signed-off-by: Thomas Gleixner <00e4cf8f46a57000a44449bf9dd8cbbcc209fd2a@linutronix.de>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs