bnxt_en: Fix 64-bit doorbell operation on 32-bit kernels

The driver requires 64-bit doorbell writes to be atomic on 32-bit
architectures.  So we redefined writeq as a new macro with spinlock
protection on 32-bit architectures.  This created a new warning when
we added a new file in a recent patchset.  writeq is defined on many
32-bit architectures to do the memory write non-atomically and it
generated a new macro redefined warning.  This warning was fixed
incorrectly in the recent patch.

Fix this properly by adding a new bnxt_writeq() function that will
do the non-atomic write under spinlock on 32-bit systems.  All callers
in the driver will now call bnxt_writeq() instead.

v2: Need to pass in bp to bnxt_writeq()
    Use lo_hi_writeq() [suggested by Florian]

Reported-by: kernel test robot <lkp@intel.com>
Fixes: f9ff5782 ("bnxt_en: introduce new firmware message API based on DMA pools")
Reviewed-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>