uart.h: fix path to PCI headers

At some point these were moved to include/drivers/

Change-Id: I5130a4d48b3bbff6ab03b6103bec0f53d88deb7b
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
diff --git a/include/uart.h b/include/uart.h
index 360e90e..4775133 100644
--- a/include/uart.h
+++ b/include/uart.h
@@ -39,8 +39,8 @@
 #include <device.h>
 
 #ifdef CONFIG_PCI
-#include <pci/pci.h>
-#include <pci/pci_mgr.h>
+#include <drivers/pci/pci.h>
+#include <drivers/pci/pci_mgr.h>
 #endif
 /**
  * @brief Options for @a UART initialization.