accel/kvm: Re-include "exec/memattrs.h" header

Commit 1e05888 ("sysemu/kvm: Remove unused headers") was
a bit overzealous while cleaning "sysemu/kvm.h" headers:
kvm_arch_post_run() returns a MemTxAttrs type, so depends on
"exec/memattrs.h" for its definition.

Fixes: 1e05888 ("sysemu/kvm: Remove unused headers")
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230619074153.44268-5-philmd@linaro.org>

include/sysemu/kvm.h

@@ -16,6 +16,7 @@
 #ifndef QEMU_KVM_H
 #define QEMU_KVM_H
 
+#include "exec/memattrs.h"
 #include "qemu/accel.h"
 #include "qom/object.h"