qed: Remove set but not used variable 'p_link'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/net/ethernet/qlogic/qed/qed_cxt.c: In function 'qed_qm_init_pf':
drivers/net/ethernet/qlogic/qed/qed_cxt.c:1401:29: warning:
 variable 'p_link' set but not used [-Wunused-but-set-variable]

commit 92fae6fb

 ("qed: FW 8.42.2.0 Queue Manager changes")
leave behind this unused variable.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>