rust: build: Fix grep warning

Fix grep warning during the build, with GNU grep 3.8
with the following command

`grep -v '^\#\|^$$' rust/bindgen_parameters`

I see the following warning

```
grep: warning: stray \ before #

--opaque-type xregs_state
--opaque-type desc_struct
--opaque-type arch_lbr_state
--opaque-type local_apic

--opaque-type x86_msi_data
--opaque-type x86_msi_addr_lo

--opaque-type kunit_try_catch

--opaque-type spinlock

--no-doc-comments
```

Signed-off-by: Vincenzo Palazzo <[email protected]>
Tested-by: Martin Rodriguez Reboredo <[email protected]>
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>

0 files changed, 0 insertions, 0 deletions