HID: rapoo: Add support for side buttons on RAPOO 0x2015 mouse

HID: rapoo: Add support for side buttons on RAPOO 0x2015 mouse

This patch adds support for handling the side buttons
on the RAPOO 0x2015 wireless mouse. These buttons were
previously not generating input events due to missing
driver logic.

The new code handles raw HID input report with Report
ID 1 and maps the side buttons to KEY_BACK and KEY_FORWARD
using the input subsystem.

Tested on a RAPOO mouse with USB ID 24AE:2015.

Signed-off-by: Nguyen Dinh Dang Duong <dangduong31205@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>