microblaze: Add missing kvm_para.h to Kbuild

Running make allmodconfig;make is throwing compilation error:
  CC      kernel/watchdog.o
In file included from ./include/linux/kvm_para.h:4:0,
                 from kernel/watchdog.c:29:
./include/uapi/linux/kvm_para.h:32:26: fatal error: asm/kvm_para.h: No
such file or directory
 #include <asm/kvm_para.h>
                          ^
compilation terminated.
make[1]: *** [kernel/watchdog.o] Error 1
make: *** [kernel/watchdog.o] Error 2

Reported-by: Michal Hocko <mhocko@kernel.org>
Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Fixes: 83f0124a

 ("microblaze: remove asm-generic wrapper headers")
Reviewed-by: Tobias Klauser <tklauser@distanz.ch>
Tested-by: Michal Hocko <mhocko@suse.com>