Enabling write-combining may also enable read reordering. The BIU is
only guaranteed to read from a 128-bit CSR or 64-bit SRAM word when
the host reads from its lowest address; otherwise the BIU may use the
latched value. Therefore we need to reinstate the read memory
barriers after the first read operation for each CSR or SRAM word.
Signed-off-by; Ben Hutchings <bhutchings@solarflare.com>
fcfa060468