Persimmon: Disable the unused PCI clocks

Change-Id: I4b735fe4e6441f99236e43b34695fdac95b8888a
Signed-off-by: Dave Frodin <dave.frodin@se-eng.com>
Reviewed-on: http://review.coreboot.org/1875
Tested-by: build bot (Jenkins)
Reviewed-by: Zheng Bao <zheng.bao@amd.com>
Reviewed-by: Marc Jones <marcj303@gmail.com>

src/mainboard/amd/persimmon/platform_cfg.h

@@ -90,7 +90,7 @@
  *  PCI SLOT 3 define at BIT3
  *  PCI SLOT 4 define at BIT4
  */
-#define PCI_CLOCK_CTRL			0x1F
+#define PCI_CLOCK_CTRL			0x07
 
 /**
  * @def SATA_CONTROLLER