vc-sm-cma: fixed kbuild problem

error logs:
  drivers/staging/vc04_services/vc-sm-cma/Kconfig:1:error: recursive dependency detected!
  drivers/staging/vc04_services/vc-sm-cma/Kconfig:1:      symbol BCM_VC_SM_CMA is selected by BCM2835_VCHIQ_MMAL
  drivers/staging/vc04_services/vchiq-mmal/Kconfig:1:     symbol BCM2835_VCHIQ_MMAL depends on BCM2835_VCHIQ
  drivers/staging/vc04_services/Kconfig:14:       symbol BCM2835_VCHIQ is selected by BCM_VC_SM_CMA
  For a resolution refer to Documentation/kbuild/kconfig-language.rst
  subsection "Kconfig recursive dependency limitations"

Tested-by: make ARCH=arm64 bcm2711_defconfig
Test platform: fedora 33
Branch: rpi-5.10.y