efi: Update stale locking comment for struct efivars
efi: Update stale locking comment for struct efivars

The comment describing how struct efivars->lock is used hasn't been
updated in sync with the code. Fix it.

Reported-by: Ard Biesheuvel <66d3c5fdaeea7ff1f996ad04f2c45e08ab38e2f5@linaro.org>
Cc: Mike Waychison <299b28f2f3ac327aab97e268a3ca5428ba100ef8@google.com>
Signed-off-by: Matt Fleming <b02f0790d66a0f0a6b369873bf6df37420fbe5dd@intel.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs