wifi: mt76: mt7996: Remove useless check in mt7996_msdu_page_get_from_cache()

wifi: mt76: mt7996: Remove useless check in mt7996_msdu_page_get_from_cache()

Get rid of useless null-pointer check in mt7996_msdu_page_get_from_cache
since we have already verfied the list is not empty.

Fixes: b1e58e137b616 ("wifi: mt76: mt7996: Introduce RRO MSDU callbacks")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/r/202510100155.MS0IXhzm-lkp@intel.com/
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://patch.msgid.link/20251014-mt7996_msdu_page_get_from_cache-remove-null-ptr-check-v1-1-fbeb7881e192@kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>