rust: kbuild: remove "`try` keyword" workaround for `bindgen` < 0.59.2
There is a workaround that has not been needed, even already after commit
08ab786556ff ("rust: bindgen: upgrade to 0.65.1"), but it does not hurt.
Thus remove it.
Reviewed-by: Tamir Duberstein <tamird@kernel.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260405235309.418950-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>