staging: rtl*: Remove tasklet callback casts

staging: rtl*: Remove tasklet callback casts

In order to make the entire kernel usable under Clang's Control Flow
Integrity protections, function prototype casts need to be avoided
because this will trip CFI checks at runtime (i.e. a mismatch between
the caller's expected function prototype and the destination function's
prototype). Many of these cases can be found with -Wcast-function-type,
which found that the rtl wifi drivers had a bunch of needless function
casts. Remove function casts for tasklet callbacks in the various drivers.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/201911150926.2894A4F973@keescook
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>