drm/panic: remove unnecessary borrow in alignment_pattern

The function `alignment_pattern` returns a static reference to a `u8`
slice. The borrow of the returned element in `ALIGNMENT_PATTERNS` is
already a reference as defined in the array definition above so this
borrow is unnecessary and removed by the compiler. Clippy notes this in
`needless_borrow`:

error: this expression creates a reference which is immediately dereferenced by the compiler
--> drivers/gpu/drm/drm_panic_qr.rs:245:9
|
245 | &ALIGNMENT_PATTERNS[self.0 - 1]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: change this to: `ALIGNMENT_PATTERNS[self.0 - 1]`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
= note: `-D clippy::needless-borrow` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::needless_borrow)]`

Remove the unnecessary borrow.

Fixes: cb5164ac43d0 ("drm/panic: Add a QR code panic screen")
Reported-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1123
Signed-off-by: Thomas Böhler <witcher@wiredspace.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://lore.kernel.org/r/20241019084048.22336-3-witcher@wiredspace.de
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>