s25f.c: Fix undefined behaviour on shift

dev_id, a uint8_t, was shifted left by 24 bits. After promotion to int,
this results in shifting into the sign bit, which is undefined
behaviour. Cast to uint32_t to prevent the promotion to signed int.

BUG=None
BRANCH=None
TEST=None

Change-Id: I88188ef2ba2af919eeae9ba08916374d31d8b989
Signed-off-by: Evan Benn <evanbenn@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/68127
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Felix Singer <felixsinger@posteo.net>
---
M s25f.c
1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/s25f.c b/s25f.c
index 67715ed..1133ef8 100644
--- a/s25f.c
+++ b/s25f.c
@@ -380,10 +380,10 @@
 	 */
 
 	uint32_t model_id =
-		dev_id[1] << 24 |
-		dev_id[2] << 16 |
-		dev_id[4] << 8  |
-		dev_id[5] << 0;
+		(uint32_t)dev_id[1] << 24 |
+		(uint32_t)dev_id[2] << 16 |
+		(uint32_t)dev_id[4] << 8  |
+		(uint32_t)dev_id[5] << 0;
 
 	if (dev_id[0] == flash->chip->manufacture_id && model_id == flash->chip->model_id)
 		return 1;

