[PATCH 0/2][4.15?] fix build when NR_CPUS == 1

[Jan Beulich <jbeulich@xxxxxxxx>]

While we've long done away with CONFIG_SMP, we still allow
CONFIG_NR_CPUS to be set to 1. Hence at least randconfig builds
may fail, and the first of the two issues addressed was actually
observed in the RISC-V bring-up work. I didn't check whether Arm
would also have issues like these.

1: sched: fix build when NR_CPUS == 1
2: x86: fix build when NR_CPUS == 1

Jan