Update "ipa_reg.h" so that register definitions support IPA hardware
version 4.5, in addition to versions 3.5.1 through v4.2.  Most of
the register definitions are the same, but in some cases fields are
added, changed, or eliminated.

Updates for a few IPA v4.5 registers are more complex, and adding
those definition will be deferred to separate patches.  This patch
only updates the register offset and field definitions, and adds
informational comments.

The only code change avoids accessing the backward compatibility
register for IPA version 4.5 in ipa_hardware_config().  Other IPA
v4.5-specific code changes will come later.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>