.gitgnore: add llvm-bpf

Signed-off-by: Felix Fietkau <[email protected]>

.gitignore

@@ -18,6 +18,7 @@
 /package/feeds
 /package/openwrt-packages
 /*.patch
+/llvm-bpf*
 key-build*
 *.orig
 *.rej