src/include: Add missing includes

Change-Id: I746ea7805bae553a146130994d8174aa2e189610
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43368
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/include/device/pci_ehci.h

@@ -5,6 +5,7 @@
 
 #include <device/device.h>
 #include <device/pci_type.h>
+#include <stdint.h>
 
 #define EHCI_BAR_INDEX		0x10
 #define PCI_EHCI_CLASSCODE	0x0c0320  /* USB2.0 with EHCI controller */