cpu-kvm: Initialize _hasKernelIRQChip in the constructor
cpu-kvm: Initialize _hasKernelIRQChip in the constructor

This class member was only correctly set to true when using an in-kernel
interrupt controller, but was un-initialized when trying to use a user-
space one and would cause trouble.

JIRA: https://gem5.atlassian.net/browse/GEM5-663

Change-Id: I71b052c6da7e8790b05a15c07e7933bc4f912785
Signed-off-by: Hsuan Hsu <22b5ca1ea7eefa4e50d967611477c8bbe4e31fba@mediatek.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/30917
Reviewed-by: Giacomo Travaglini <8eef13a4f970e2e9372c8d26ad0737b760f99c02@arm.com>
Reviewed-by: Andreas Sandberg <c9f5686ee5bd561c93f9de79681eee75bfa7f36e@arm.com>
Maintainer: Giacomo Travaglini <8eef13a4f970e2e9372c8d26ad0737b760f99c02@arm.com>
Maintainer: Andreas Sandberg <c9f5686ee5bd561c93f9de79681eee75bfa7f36e@arm.com>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

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