[hermon] Use reset value suitable for ConnectX-3

[hermon] Use reset value suitable for ConnectX-3

The programming documentation states that the reset magic value is
"0x00000001 (Big Endian)", and the current code matches this by using
the value 0x01000000 for the implicitly little-endian writel().

Inspection of the FlexBoot source code reveals an exciting variety of
reset values, some suggestive of confusion around endianness.

Experimentation suggests that the value 0x01000001 works reliably
across a wide range of hardware.

Debugged-by: Christian Iversen <ci@iversenit.dk>
Signed-off-by: Michael Brown <mcb30@ipxe.org>