tree: Make internal functions static

None of these functions are used outside of the files they are defined
in, so make them all static.

Change-Id: Ie9cbe12d289bcedacf2f1bf483ae64ef8039ccc1
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/33667
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/it87spi.c b/it87spi.c
index 13b3aae..9e7a8ea 100644
--- a/it87spi.c
+++ b/it87spi.c
@@ -57,7 +57,7 @@
 	sio_write(port, 0x02, 0x02);
 }
 
-uint16_t probe_id_ite(uint16_t port)
+static uint16_t probe_id_ite(uint16_t port)
 {
 	uint16_t id;