staging/rdma/hfi1: Fix error in hfi1 driver build

hfi1 driver build fails with the following error:
In function ‘handle_receive_interrupt’:
error: implicit declaration of function ‘skip_rcv_packet’ [-Werror=implicit-function-declaration]
    last = skip_rcv_packet(&packet, thread);
    ^
This is due to the inclusion of the skip_rcv_packet() in the
CONFIG_PRESCAN_RXQ ifdef block. This function is independent of
CONFIG_PRESCAN_RXQ and should be outside this block.

Fixes: 82c2611d ("staging/rdma/hfi1: Handle packets with invalid RHF on context 0")
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>