iichid(4): Read wMaxInputLength bytes over I2C even if we discards data

For some devices e.g. ITE5570 it is not enough to read HID-over-I2C
input length header of RESET command response to acknowledge interrupt.
Do a full-size read to avoid interrupt storm.

Sponsored by: Future Crew LLC
MFC after: 2 month
Differential Revision: https://reviews.freebsd.org/D48957