mmc: sdhci-msm: Make function sdhci_msm_dump_vendor_regs() static

Fix sparse build warning:

drivers/mmc/host/sdhci-msm.c:1888:6: warning:
 symbol 'sdhci_msm_dump_vendor_regs' was not declared. Should it be static?
Signed-off-by: Hulk Robot <hulkci@huawei.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20200702020347.77214-1-weiyongjun1@huawei.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-msm.c

@@ -2068,7 +2068,7 @@ static int sdhci_msm_start_signal_voltage_switch(struct mmc_host *mmc,
 #define SDHCI_MSM_DUMP(f, x...) \
 	pr_err("%s: " DRIVER_NAME ": " f, mmc_hostname(host->mmc), ## x)
 
-void sdhci_msm_dump_vendor_regs(struct sdhci_host *host)
+static void sdhci_msm_dump_vendor_regs(struct sdhci_host *host)
 {
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);