netifd: bridge: Fix format string position

netifd: bridge: Fix format string position

This fixes the following compile error:
error: format not a string literal, argument types not checked [-Werror=format-nonliteral]

blobmsg_printf() has the following signature:
int blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)

Signed-off-by: Hauke Mehrtens <[email protected]>