powerpc/sysdev/ipic: check primary_ipic NULL pointer before using it

[Michael Ellerman]

On Mon, 2018-08-27 at 08:27:27 UTC, Christophe Leroy wrote:
> ipic_get_mcp_status() is used by targets implementing NMI
> watchdog in target specific machine check handler in order
> to known whether a machine check results from a watchdog
> NMI reset.
> 
> In case of very early machine check, primary_ipic pointer
> might not have been set yet, so ipic_get_mcp_status() needs
> to check it for nullity before using it.
> 
> Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/6beb3381b12793726783a5e9428250

cheers