core/namespace: drop bitfield annotations from boolean fields

core/namespace: drop bitfield annotations from boolean fields

Such microoptimization makes sense when the structure is used in many many copies,
but here's it's not, and the few bytes we save are not worth the extra code the
compiler has to generate:

    return  ns_info->mount_apivfs ||
            ns_info->protect_control_groups ||
            ns_info->protect_kernel_tunables ||
            ...
before:
  49b187:       48 8b 45 f8             mov    -0x8(%rbp),%rax
  49b18b:       0f b6 00                movzbl (%rax),%eax
  49b18e:       83 e0 80                and    $0xffffff80,%eax
  49b191:       84 c0                   test   %al,%al
  49b193:       75 32                   jne    49b1c7 <namespace_info_mount_apivfs+0x80>
  49b195:       48 8b 45 f8             mov    -0x8(%rbp),%rax
  49b199:       0f b6 00                movzbl (%rax),%eax
  49b19c:       83 e0 08                and    $0x8,%eax
  49b19f:       84 c0                   test   %al,%al
  49b1a1:       75 24                   jne    49b1c7 <namespace_info_mount_apivfs+0x80>
  49b1a3:       48 8b 45 f8             mov    -0x8(%rbp),%rax
  49b1a7:       0f b6 00                movzbl (%rax),%eax
  49b1aa:       83 e0 10                and    $0x10,%eax
  49b1ad:       84 c0                   test   %al,%al
  49b1af:       75 16                   jne    49b1c7 <namespace_info_mount_apivfs+0x80>

after:
  49b024:       48 8b 45 f8             mov    -0x8(%rbp),%rax
  49b028:       0f b6 40 07             movzbl 0x7(%rax),%eax
  49b02c:       84 c0                   test   %al,%al
  49b02e:       75 2e                   jne    49b05e <namespace_info_mount_apivfs+0x7a>
  49b030:       48 8b 45 f8             mov    -0x8(%rbp),%rax
  49b034:       0f b6 40 03             movzbl 0x3(%rax),%eax
  49b038:       84 c0                   test   %al,%al
  49b03a:       75 22                   jne    49b05e <namespace_info_mount_apivfs+0x7a>
  49b03c:       48 8b 45 f8             mov    -0x8(%rbp),%rax
  49b040:       0f b6 40 04             movzbl 0x4(%rax),%eax
  49b044:       84 c0                   test   %al,%al
  49b046:       75 16                   jne    49b05e <namespace_info_mount_apivfs+0x7a>