HID: core: ensure the allocated report buffer can contain the reserved report ID

commit 4f15ee98304b96e164ff2340e1dfd6181c3f42aa upstream.

When the report ID is not used, the low level transport drivers expect
the first byte to be 0. However, currently the allocated buffer not
account for that extra byte, meaning that instead of having 8 guaranteed
bytes for implement to be working, we only have 7.

Reported-by: Alan Stern <stern@rowland.harvard.edu>
Closes: https://lore.kernel.org/linux-input/c75433e0-9b47-4072-bbe8-b1d14ea97b13@rowland.harvard.edu/


Cc: stable@vger.kernel.org
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://patch.msgid.link/20250710-report-size-null-v2-1-ccf922b7c4e5@kernel.org


Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>