wifi_hal: Rename to 'hal_wifi'

Renaming the wifi HIDL implementation to 'hal_wifi' from 'wifi_hal_legacy'
to conform with HIDL style guide.

Denials:
01-01 21:55:23.896  2865  2865 I android.hardware.wifi@1.0-service:
wifi_hal_legacy is starting up...
01-01 21:55:23.898  2865  2865 W android.hardware.wifi@1.0-service:
/odm/lib64/hw/ does not exit.
01-01 21:55:23.899  2865  2865 F android.hardware.wifi@1.0-service:
service.cpp:59] Check failed: service->registerAsService("wifi") ==
android::NO_ERROR (service->registerAsService("wifi")=-2147483646,
android::NO_ERROR=0) Failed to register wifi HAL
01-01 21:55:23.899  2865  2865 F libc    : Fatal signal 6 (SIGABRT),
code -6 in tid 2865 (android.hardwar)
01-01 21:55:23.901   377   377 W         : debuggerd: handling request:
pid=2865 uid=2000 gid=2000 tid=2865
01-01 21:55:23.907  2867  2867 E         : debuggerd: Unable to connect
to activity manager (connect failed: Connection refused)
01-01 21:55:23.908  2867  2867 F DEBUG   : *** *** *** *** *** *** ***
*** *** *** *** *** *** *** *** ***
01-01 21:55:23.908  2867  2867 F DEBUG   : Build fingerprint:
'Android/aosp_angler/angler:7.0/NYC/rpius10031052:userdebug/test-keys'
01-01 21:55:23.908  2867  2867 F DEBUG   : Revision: '0'
01-01 21:55:23.908  2867  2867 F DEBUG   : ABI: 'arm64'
01-01 21:55:23.908  2867  2867 F DEBUG   : pid: 2865, tid: 2865, name:
android.hardwar  >>> /system/bin/hw/android.hardware.wifi@1.0-service
<<<
01-01 21:55:23.909  2867  2867 F DEBUG   : signal 6 (SIGABRT), code -6
(SI_TKILL), fault addr --------
01-01 21:55:23.910  2867  2867 F DEBUG   : Abort message:
'service.cpp:59] Check failed: service->registerAsService("wifi") ==
android::NO_ERROR (service->registerAsService("wifi")=-2147483646,
android::NO_ERROR=0) Failed to register wifi HAL'

Bug: 31821133
Test: Compiled and ensured that the selinux denials are no longer
present in logs.
Change-Id: I5bbbcad307e9bb9e59fff87e2926751b3aecc813