mmc: sdhci-pci-o2micro: Make some symbols static

Fix the following sparse warning:

drivers/mmc/host/sdhci-pci-o2micro.c:497:6: warning: symbol
'sdhci_pci_o2_set_clock' was not declared. Should it be static?
drivers/mmc/host/sdhci-pci-o2micro.c:512:5: warning: symbol
'sdhci_pci_o2_probe_slot' was not declared. Should it be static?
drivers/mmc/host/sdhci-pci-o2micro.c:581:5: warning: symbol
'sdhci_pci_o2_probe' was not declared. Should it be static?
drivers/mmc/host/sdhci-pci-o2micro.c:786:5: warning: symbol
'sdhci_pci_o2_resume' was not declared. Should it be static?

Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: Zou Wei <[e-mail]>
Acked-by: Adrian Hunter <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/host/sdhci-pci-o2micro.c

···
 	}
 }
 
-void sdhci_pci_o2_set_clock(struct sdhci_host *host, unsigned int clock)
+static void sdhci_pci_o2_set_clock(struct sdhci_host *host, unsigned int clock)
 {
 	u16 clk;
 
···
 	sdhci_o2_enable_clk(host, clk);
 }
 
-int sdhci_pci_o2_probe_slot(struct sdhci_pci_slot *slot)
+static int sdhci_pci_o2_probe_slot(struct sdhci_pci_slot *slot)
 {
 	struct sdhci_pci_chip *chip;
 	struct sdhci_host *host;
···
 	return 0;
 }
 
-int sdhci_pci_o2_probe(struct sdhci_pci_chip *chip)
+static int sdhci_pci_o2_probe(struct sdhci_pci_chip *chip)
 {
 	int ret;
 	u8 scratch;
···
 }
 
 #ifdef CONFIG_PM_SLEEP
-int sdhci_pci_o2_resume(struct sdhci_pci_chip *chip)
+static int sdhci_pci_o2_resume(struct sdhci_pci_chip *chip)
 {
 	sdhci_pci_o2_probe(chip);
 	return sdhci_pci_resume_host(chip);