hw/arm/virt: Simplify create_its()

hw/arm/virt: Simplify create_its()

No need to strstr() check the class name when we can use
kvm_irqchip_in_kernel() to check if the ITS from the host can be used.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Gustavo Romero <gustavo.romero@linaro.org>
Message-id: 20250628195722.977078-4-gustavo.romero@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>