HID: lenovo: Fix buffer over-read and unaligned access in X12 Tab raw_event handler

HID: lenovo: Fix buffer over-read and unaligned access in X12 Tab raw_event handler

In lenovo_raw_event(), the X12 Tab keyboard handler reads a 4-byte
little-endian value from the raw HID report buffer but:

  1. The size guard is size >= 3, while the access reads 4 bytes.
     A malformed 3-byte report with ID 0x03 would over-read the
     buffer by one byte.

  2. Casting u8 *data directly to __le32 * can trigger unaligned
     access faults on architectures like ARM, MIPS, and SPARC,
     because HID input buffers carry no alignment guarantee.
     (e.g. uhid payloads start at offset 6 in struct uhid_event,
     giving only 2-byte alignment.)

Fix both by tightening the size check to >= 4 and replacing the
open-coded cast + le32_to_cpu() with get_unaligned_le32(), which
handles the LE-to-CPU conversion safely regardless of alignment.

Link: https://sashiko.dev/#/message/20260512044911.99B6DC2BCB0%40smtp.kernel.org
Assisted-by: CLAUDE:claude-4-sonnet
Signed-off-by: Kean <rh_king@163.com>
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>