mt76: mt7603: dynamically alloc mcu req in mt7603_mcu_set_eeprom

Do not allocate mcu requests on the stack in mt7603_mcu_set_eeprom
in order to avoid the following warning:

Warning: the frame size of 1032 bytes is larger than 1024 bytes
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>