broadcom-sta-dkms doensn't build against v5.6 mainline kernel: error: implicit declaration of function ‘ioremap_nocache’

broadcom-sta-dkms.make.log:

 CC [M] /var/lib/dkms/broadcom-sta/6.30.223.271/build/src/shared/linux_osl.o
/var/lib/dkms/broadcom-sta/6.30.223.271/build/src/shared/linux_osl.c: In function ‘osl_reg_map’:
/var/lib/dkms/broadcom-sta/6.30.223.271/build/src/shared/linux_osl.c:949:10: error: implicit declaration of function ‘ioremap_nocache’; did you mean ‘ioremap_cache’? [-Werror=implicit-function-declaration]
  949 | return (ioremap_nocache((unsigned long)pa, (unsigned long)size));
      | ^~~~~~~~~~~~~~~
      | ioremap_cache