drivers: rmnet_shs: Fix max flows mem leak

Previously we would break out after allocating a flow node
if we exceeded our max flow limit.

This will move the limit check before we allocate memory
so that we don't leak memory

CRs-Fixed: 2446108
Change-Id: I0456514f4533f80c2ee5524095b1b812f9ae1a52
Acked-by: Raul Martinez <mraul@qti.qualcomm.com>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>