LoongArch: KVM: Add include defining struct cpu_feature

LoongArch: KVM: Add include defining struct cpu_feature

Traditionally <linux/mod_devicetable.h> was a header defining a plethora
of structs, among them struct cpu_features. This was split now with the
objective that only the relevant bits are included.

Currently <linux/mod_devicetable.h> is transitively included in
arch/loongarch/kvm/main.c via:

	arch/loongarch/kvm/main.c ->
	<linux/kvm_host.h> ->
	<linux/entry-virt.h> ->
	<linux/resume_user_mode.h> ->
	<linux/memcontrol.h> ->
	<linux/cgroup.h> ->
	<linux/kernel_stat.h> ->
	<linux/interrupt.h> ->
	<linux/hardirq> ->
	<asm/hardirq.h> ->
	<linux/irq.h> ->
	<asm/irq.h> ->
	<linux/irqdomain.h> ->
	<linux/of.h> ->
	<linux/mod_devicetable.h>

To keep struct cpu_features available once <linux/of.h> stops including
<linux/mod_devicetable.h>, include it here explicitly.

Acked-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Bibo Mao <maobibo@loongson.cn>
Acked-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://patch.msgid.link/052feec0e04ea8f5b2706a19a5b236679eed0aba.1782808461.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@baylibre.com>