SVN r303890 breaks build

[Michael Butler]

The switch to device_t breaks the user-space compilation with ..

Building /usr/obj/usr/src/lib/libkvm/kvm.o
--- kvm.o ---
In file included from /usr/src/lib/libkvm/kvm.c:50:
/usr/obj/usr/src/tmp/usr/include/sys/pcpu.h:163:2: error: unknown type
name 'device_t'
        device_t        pc_device;
        ^
1 error generated.
*** [kvm.o] Error code 1

	imb