pci: Adjust video BIOS debugging to be SPL-friendly

A hex value is expected for the VGA mode. Add a 0x prefix, since the #
construct is not supported in SPL. We don't want to add it, due to
code-size constraints.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/pci/pci_rom.c b/drivers/pci/pci_rom.c
index bdfd1f0..503feb1 100644
--- a/drivers/pci/pci_rom.c
+++ b/drivers/pci/pci_rom.c
@@ -273,7 +273,7 @@
 		defined(CONFIG_FRAMEBUFFER_VESA_MODE)
 	vesa_mode = CONFIG_FRAMEBUFFER_VESA_MODE;
 #endif
-	debug("Selected vesa mode %#x\n", vesa_mode);
+	debug("Selected vesa mode 0x%x\n", vesa_mode);
 
 	if (exec_method & PCI_ROM_USE_NATIVE) {
 #ifdef CONFIG_X86
@@ -324,7 +324,7 @@
 		log_debug("done\n");
 #endif
 	}
-	debug("Final vesa mode %#x\n", mode_info.video_mode);
+	debug("Final vesa mode %x\n", mode_info.video_mode);
 	ret = 0;
 
 err: