wifi: fix a use of an uninitialized value

This `if` is executed once, so using `legacy_status` from a prior
execution is nonsensical.

Caught by the static analyzer:
> hardware/interfaces/wifi/1.5/default/wifi_chip.cpp:1053:39: warning:
1st function call argument is an uninitialized value
[clang-analyzer-core.CallAndMessage]

Bug: 173999527
Test: atest -c VtsHalWifiApV1_5TargetTest
Merged-In: Ib81f1496be53e453d9c99ede129a77bdaf860de7
Change-Id: Ib81f1496be53e453d9c99ede129a77bdaf860de7