main/linux-vanilla: increase number of CPUs to 64 for x86

fixes #10768
increase CONFIG_NR_CPUS to 64 for x86 on  linux-virt and linux-vanilla
CONFIG_NR_CPUS_DEFAULT is left at 32 for now because each CPU need
8KB of RAM
1 job for !50 with linux-x86-nrcpus-64 in 20 seconds (queued for 3 seconds)
detached
Status Job ID Name Coverage
  Lint
failed #698
x86_64 docker-alpine allowed to fail
lint

00:00:20

 
Name Stage Failure
failed
lint Lint
No job log