How to modify Makefile to exclude -mfloat-abi=soft ?

[bern]

I use Beagle Bone Black (BBB) and Arch few days
$this->bbcode_second_pass_code('', 'Linux BBB 5.2.9-1-ARCH #1 PREEMPT Sat Aug 17 22:14:34 UTC 2019 armv7l GNU/Linux')
I would like to build driver/module for Realtek RLT8821CU WIFI AC dongle.
I haven't found RLT8821CU driver for my BBB in the Arch ARM repository.

BBB has the same architecture as RPI armv7l/armhf so I thought I could use driver for RPI.
I found https://github.com/brektrou/rtl8821CU and adjusted for RPI. I've build it in the Rasbian environment (kernel 4.19.66-v7+) and works OK for my RPI2.
I have applied the same adjustments (marks green):
https://github.com/zebulon2/rtl8812au/c ... 3be1538094
to BBB and unfortunately during building I receive:
$this->bbcode_second_pass_code('', 'gcc: error: -mfloat-abi=soft and -mfloat-abi=hard may not be used together')
This is strange because in the makefile I have only:
$this->bbcode_second_pass_code('', 'EXTRA_CFLAGS += -mfloat-abi=hard')
see the line 1180 of Makefile
http://paste.ubuntu.com/p/KYw5YQBk3C/
which worked for RPI.
What should I adjust in the Makefile to disable -mfloat-abi=soft?