RDMA/bnxt_re: Fix buffer overflow in debugfs code

RDMA/bnxt_re: Fix buffer overflow in debugfs code

Add some bounds checking to prevent memory corruption in
bnxt_re_cc_config_set().  This is debugfs code so the bug can only be
triggered by root.

Fixes: 656dff55da19 ("RDMA/bnxt_re: Congestion control settings using debugfs hook")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://patch.msgid.link/a6b081ab-55fe-4d0c-8f69-c5e5a59e9141@stanley.mountain
Acked-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>