wimax: Remove unnecessary alloc/OOM messages, alloc cleanups

alloc failures already get standardized OOM
messages and a dump_stack.

Convert kzalloc's with multiplies to kcalloc.
Remove now unused size variables.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>