math: Introduce div64_long

Add a div64_long macro which is used to devide a 64bit number by a long (which
can be 4 bytes on 32bit systems and 8 bytes on 64bit systems).

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Cc: johnstul@us.ibm.com
Link: http://lkml.kernel.org/r/1331829374-31543-1-git-send-email-levinsasha928@gmail.com


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>