genirq: Increase the number of interrupters

commit 99ff6bd2532980d02bb2fa69c2f88463f697304c from
git@git.assembla.com:cavium/WindRiver.linux.git

Currently the maximum number of interrupters is capped at 8260 (64 +
8196) in most of the architectures were CONFIG_SPARSE_IRQ is selected.
This upper limit is not sufficient for couple of existing SoC's from
Marvell.
For eg: Octeon TX2 series of processors support a maximum of 32K
interrupters.

Bump up the upper limit from 8196 to 65536.

Change-Id: I124cd28f717620187ffece1089999b4e0298c183
Signed-off-by: George Cherian <george.cherian@marvell.com>
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/80361


Reviewed-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Tested-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>