To avoid too much #if soup, e_aes.c uses a lot of dummy functions that
just call |abort|. This change makes them all static, which they should
have been all along.

Change-Id: I696f8a0560cf99631ed7adb42d1af10003db4a63
Reviewed-on: https://boringssl-review.googlesource.com/6004
Reviewed-by: Adam Langley <agl@google.com>