mmc: sdhci-pci: Make function amd_sdhci_reset static

Fix sparse warnings:

drivers/mmc/host/sdhci-pci-core.c:1599:6: warning: symbol 'amd_sdhci_reset' was not declared. Should it be static?
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: Nzhengbin <zhengbin13@huawei.com>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-pci-core.c

@@ -1596,7 +1596,7 @@ static u32 sdhci_read_present_state(struct sdhci_host *host)
 	return sdhci_readl(host, SDHCI_PRESENT_STATE);
 }
 
-void amd_sdhci_reset(struct sdhci_host *host, u8 mask)
+static void amd_sdhci_reset(struct sdhci_host *host, u8 mask)
 {
 	struct sdhci_pci_slot *slot = sdhci_priv(host);
 	struct pci_dev *pdev = slot->chip->pdev;