powerpc/pseries/ras: Remove unused variable 'status'

The last use of 'status' was removed in 2012. Remove the variable to
fix this W=1 compile error.

../arch/powerpc/platforms/pseries/ras.c: In function ‘ras_epow_interrupt’:
../arch/powerpc/platforms/pseries/ras.c:318:6: error: variable ‘status’ set but not used [-Werror=unused-but-set-variable]
  318 |  int status;
      |      ^~~~~~

Fixes: 55fc0c56 ("powerpc/pseries: Parse and handle EPOW interrupts")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210104143206.695198-3-clg@kaod.org