KVM: x86: Replace growing set of *_in_guest bools with a u64

KVM: x86: Replace growing set of *_in_guest bools with a u64

Store each "disabled exit" boolean in a single bit rather than a byte.

No functional change intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Link: https://lore.kernel.org/r/20250530185239.2335185-2-jmattson@google.com
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20250626001225.744268-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>