MIPS: SMP-CPS: Remove duplicate assignment of core in play_dead

The merge of commit f875a832 ("MIPS: Abstract CPU core & VP(E) ID
access through accessor functions") ended up creating a duplicate
assignment of core during the rebase on commit bac06cf0 ("MIPS:
smp-cps: Fix potentially uninitialised value of core"). Remove the
duplicate.

Fixes: f875a832

 ("MIPS: Abstract CPU core & VP(E) ID access through accessor functions")
Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17955/
Signed-off-by: James Hogan <jhogan@kernel.org>