x86: fix "format not a string literal" errors

Fix the following two compilation errors:

x86/msr.c: In function ‘test_msr_rw’:
x86/msr.c:94:5: error: format not a string literal and no format arguments [-Werror=format-security]
     report(sptr, expected == r);
          ^

x8e/vmx.c: In function ‘test_vmx_caps’:
x86/vmx.c:1412:3: error: format not a string literal and no format arguments [-Werror=format-security]
   report(vmx_ctl_msr[n].name, ok);
      ^

Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>