HID: asus: avoid memory leak in asus_report_fixup()

HID: asus: avoid memory leak in asus_report_fixup()

The asus_report_fixup() function was returning a newly allocated
kmemdup()-allocated buffer, but never freeing it.  Switch to
devm_kzalloc() to ensure the memory is managed and freed automatically
when the device is removed.

The caller of report_fixup() does not take ownership of the returned
pointer, but it is permitted to return a pointer whose lifetime is at
least that of the input buffer.

Also fix a harmless out-of-bounds read by copying only the original
descriptor size.

Assisted-by: Gemini-CLI:Google Gemini 3
Signed-off-by: Günther Noack <gnoack@google.com>
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>