td-exception: clippy error `masking with zero`

https://github.com/confidential-containers/td-shim/blob/ccdde480f5fc9adb786d0d89603d2d42c47e5e36/td-exception/src/idt.rs#L133

When using the cargo clippy with the latest nightly toolchain, it reports error:

error: &-masking with zero
   --> td-exception/src/idt.rs:130:1
    |
130 | / bitflags! {
131 | |     pub struct IdtFlags: u8 {
132 | |         const PRESENT = 1 << 7;
133 | |         // RING_0 is 0 << 5
...   |
141 | |     }
142 | | }
    | |_^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#bad_bit_mask
    = note: `#[deny(clippy::bad_bit_mask)]` on by default
    = note: this error originates in the macro `__impl_bitflags` which comes from the expansion of the macro `bitflags` (in Nightly builds, run with -Z macro-backtrace for more info)

confidential-containers / td-shim

td-exception: clippy error `masking with zero` #587