HID: wacom: Fix OOB write in wacom_hid_set_device_mode()

In the Linux kernel, the following vulnerability has been resolved: HID: wacom: Fix OOB write in wacom_hid_set_device_mode() wacom_hid_set_device_mode() currently assumes that the HID_DG_INPUTMODE usage is always located in the first field (field[0]) of the feature report. However, a device can specify HID_DG_INPUTMODE in a different field. If HID_DG_INPUTMODE is in a field other than the first one and the first field has a report_count smaller than the usage_index of HID_DG_INPUTMODE, this leads to an out-of-bounds write to r->field[0]->value. Fix this by storing the field index of HID_DG_INPUTMODE in 'struct hid_data' during feature mapping. In wacom_hid_set_device_mode(), use this stored field index to access the correct field and add bounds checks to ensure both the field index and the value index are within valid ranges before writing.