irq/matrix: Fix memory overallocation

mainline inclusion
from mainline-4.20
commit 57f01796
category: bugfix
bugzilla: 5769
CVE: NA

-------------------------------------------------

IRQ_MATRIX_SIZE is the number of longs needed for a bitmap, multiplied by
the size of a long, yielding a byte count. But it is used to size an array
of longs, which is way more memory than is needed.

Change IRQ_MATRIX_SIZE so it is just the number of longs needed and the
arrays come out the correct size.

Fixes: 2f75d9e1 ("genirq: Implement bitmap matrix allocator")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: KY Srinivasan <kys@microsoft.com>
Link: https://lkml.kernel.org/r/1541032428-10392-1-git-send-email-mikelley@microsoft.com


Signed-off-by: Cheng Jian <cj.chengjian@huawei.com>
Reviewed-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>