wifi: rt2x00: silence sparse warnings

Clearly writing __le32 was intended here, so just put the
right casts into the code to silence sparse about it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240223114023.ce0c714124e9.I2b5710b761f63522574fbe7654d37151c31e0b77@changeid