exclude the {to,from}-kernel.sh scripts

Commit 5438e8d ("rename `sync-kernel.sh` -> `to-kernel.sh`")
renamed the `sync-kernel.sh` script to `to-kernel.sh` and thus it should
be updated to exclude itself.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>

Author: BennoLossin

to-kernel.sh

@@ -60,7 +60,8 @@ head=$(git rev-parse HEAD)
 git am                                              \
     --signoff                                       \
     --directory="rust/pin-init"                     \
-    --exclude="rust/pin-init/sync-kernel.sh"        \
+    --exclude="rust/pin-init/to-kernel.sh"          \
+    --exclude="rust/pin-init/from-kernel.sh"        \
     --exclude="rust/pin-init/LICENSE-APACHE"        \
     --exclude="rust/pin-init/LICENSE-MIT"           \
     --exclude="rust/pin-init/CHANGELOG.md"          \