Remove the 'of_match_ptr()' macro to fix the warning when CONFIG_OF is
not selected.

drivers/mmc/host/owl-mmc.c:677:34: warning: unused variable 'owl_mmc_of_match'
[-Wunused-const-variable]
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://lore.kernel.org/r/20200621025330.10561-1-mani@kernel.org
Fixes: ff65ffe4 ("mmc: Add Actions Semi Owl SoCs SD/MMC driver")
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>