net: ipa: add a parameter to suspend registers

The SUSPEND_INFO, SUSPEND_EN, SUSPEND_CLR registers represent
endpoint IDs in a bit mask.  When more than 32 endpoints are
supported, these registers will be replicated as needed to represent
the number of supported endpoints.  Update the definitions of these
registers to have a stride of 4 bytes, and update the code that
operates them to select the proper offset and bit.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>