net: ipa: add "gsi_v4.11.c"

The next patch adds a GSI register field that is only valid starting
at IPA v4.11.  Create "gsi_v4.11.c" from "gsi_v4.9.c", changing only
the name of the public regs structure it defines.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>