powerpc/pseries: add missing cpumask.h include file

[Michael Ellerman]

On Tue, 2018-10-23 at 01:32:12 UTC, Tyrel Datwyler wrote:
> Build error is encountered when inlcuding <asm/rtas.h> if no explicit or
> implicit include of cpumask.h exists in the including file.
> 
> In file included from arch/powerpc/platforms/pseries/hotplug-pci.c:3:0:
> ./arch/powerpc/include/asm/rtas.h:360:34: error: unknown type name 'cpumask_var_t'
>  extern int rtas_online_cpus_mask(cpumask_var_t cpus);
>                                   ^
> ./arch/powerpc/include/asm/rtas.h:361:35: error: unknown type name 'cpumask_var_t'
>  extern int rtas_offline_cpus_mask(cpumask_var_t cpus);
> 
> Fixes: 120496ac2d2d ("powerpc: Bring all threads online prior to migration/hibernation")
> Signed-off-by: Tyrel Datwyler <tyreld at linux.vnet.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/8dce6b2215eaa91dbf04463e11098a

cheers