samples: usb: hid-mouse: remove get_report_cb
samples: usb: hid-mouse: remove get_report_cb

Removed get_report_cb as it was an incorrect implementation
of Get_Report request. Correct response would be returning
current report value, not report descriptor.

Signed-off-by: Marcin Szymczyk <8fc8da9290e253bcb8b4ee9416a0003a2a8e3fa1@nordicsemi.no>

punitvara/zephyr,finikorg/zephyr,Vudentz/zephyr,punitvara/zephyr,galak/zephyr,ldts/zephyr,ldts/zephyr,explora26/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,punitvara/zephyr,explora26/zephyr,galak/zephyr,Vudentz/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,finikorg/zephyr,Vudentz/zephyr,explora26/zephyr,finikorg/zephyr,explora26/zephyr,finikorg/zephyr,Vudentz/zephyr,punitvara/zephyr,punitvara/zephyr,nashif/zephyr,nashif/zephyr,galak/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,explora26/zephyr