net: qualcomm: rmnet: Remove redundant command check

The command packet size is already checked once in
rmnet_map_deaggregate() for the header, packet and trailer size, so
this additional check is not needed.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>