Fix more warnings about old-style prototypes.

Replace |()| with |(void)| in some prototypes to avoid compiler
warnings about old-style prototypes when building in some non-default
configurations for ARM.

Change-Id: Id57825084941c997bb7c41ec8ed94962f97ff732
Reviewed-on: https://boringssl-review.googlesource.com/5570
Reviewed-by: Adam Langley <agl@google.com>
2 files changed