Add the remaining GSI register offset definitions.  Use gsi_reg()
rather than the corresponding GSI_*_OFFSET() macros to get the
offsets for these registers, and get rid of the macros.

Note that we are now defining information for the HW_PARAM_2
register, and that doesn't appear until IPA v3.5.1.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>