irqchip/mbigen: Make CONFIG_HISILICON_IRQ_MBIGEN a hidden option

This config is selected by CONFIG_ARCH_HISI, so there is no point to have it
user configurable.

While at it move the config option to the proper place in the alphabetically
sorted option list.

Requested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ma Jun <majun258@huawei.com>
Cc: mark.rutland@arm.com
Cc: jason@lakedaemon.net
Cc: marc.zyngier@arm.com
Cc: Catalin.Marinas@arm.com
Cc: guohanjun@huawei.com
Cc: Will.Deacon@arm.com
Cc: huxinwei@huawei.com
Cc: lizefan@huawei.com
Cc: dingtianhong@huawei.com
Cc: zhaojunhua@hisilicon.com
Cc: liguozhu@hisilicon.com
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1458723993-21044-3-git-send-email-majun258@huawei.com


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