dissector: proto_80211_mac_hdr: Fix compiler warnings

Fix two signed/unsigned comparison warnings by changing variable types.
Fix warnings about unused parameters by removing all of the
unimplemented functions and replacing them with one *_unimplemented()
function.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
rnd: Change parameter type in randombytes_{weak,strong}

Change parameter type for the length to size_t since this is what is
passed to them and is expected by read_exact().

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
rnd: Fix compiler warning

Fix the following compiler warning that occurs when building with "-W
-Wall -Wextra":

rnd.c: In function ‘randombytes_strong’:
rnd.c:50:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
cpusched: Fix compiler warnings

Fix the following compiler warnings that occur when building with "-W
-Wall -Wextra":

cpusched.c: In function ‘get_appropriate_cpu’:
cpusched.c:28:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
cpusched.c:29:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>