KVM: Shrink struct kvm_mmu_memory_cache

Move the 'capacity' member around to make use of the padding hole on 64
bit systems instead of introducing yet another one.

This allows us to save 8 bytes per instance for 64 bit builds of which,
e.g., x86's struct kvm_vcpu_arch has a few.

Signed-off-by: Mathias Krause <minipli@grsecurity.net>
Link: https://lore.kernel.org/r/20230217193336.15278-3-minipli@grsecurity.net


Signed-off-by: Sean Christopherson <seanjc@google.com>