Define the fields for the ENDP_INIT_DEAGGR, ENDP_INIT_RSRC_GRP,
ENDP_INIT_SEQ, ENDP_STATUS, and ENDP_FILTER_ROUTER_HSH_CFG, and
IPA_IRQ_UC IPA registers for all supported IPA versions.

Create enumerated types to identify fields for these IPA registers.
Use IPA_REG_FIELDS() and IPA_REG_STRIDE_FIELDS() to specify the
field mask values defined for these registers, for each supported
version of IPA.

Use ipa_reg_encode() and ipa_reg_bit() to build up the values to be
written to these registers, remove an inline function and all the
*_FMASK symbols that are now no longer used.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>