bnxt_en: reduce timeout on initial HWRM calls

bnxt_en: reduce timeout on initial HWRM calls

Orabug: 29357977

Testing with DIM enabled on older kernels indicated that firmware calls
were slower than expected.  More detailed analysis indicated that the
default 25us delay was higher than necessary.  Reducing the time spend in
usleep_range() for the first several calls would reduce the overall
latency of firmware calls on newer Intel processors.

Signed-off-by: Andy Gospodarek <gospo@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 9751e8e714872aa650b030e52a9fafbb694a3714)
Signed-off-by: Brian Maly <brian.maly@oracle.com>
Conflicts:
	drivers/net/ethernet/broadcom/bnxt/bnxt.c