Add one new file vga-pci.h and cleanup on all platforms

Functions pci_vga_init() and pci_cirrus_vga_init() are declared
in pc.h. That prevents other platforms (e.g. sPAPR) to use them.

This patch is to create one new file vga-pci.h and move the
declarations to vga-pci.h, so that they can be shared by
all platforms. This patch also cleans up on all platforms.

Signed-off-by: Li Zhang <zhlcindy@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/hw/pc.c b/hw/pc.c
index e8bcfc0..3ed1a3c 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -51,6 +51,7 @@
 #include "exec-memory.h"
 #include "arch_init.h"
 #include "bitmap.h"
+#include "vga-pci.h"
 
 /* output Bochs bios info messages */
 //#define DEBUG_BIOS