wifi: mac80211: clean up assignments to pointer cache.

wifi: mac80211: clean up assignments to pointer cache.

The assignment to pointer cache in function mesh_fast_tx_gc can
be made at the declaration time rather than a later assignment.
There are also 3 functions where pointer cache is being initialized
at declaration time and later re-assigned again with the same
value, these are redundant and can be removed.

Cleans up code and three clang scan build warnings:
warning: Value stored to 'cache' during its initialization is never
read [deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://msgid.link/20240215232151.2075483-1-colin.i.king@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>