drivers: modem: constify modem_cmd and setup_cmd structures

modem_cmd and setup_cmd structures are used only to store static
information about commands to be sent and replies to be
received. Reference it as const, so that it is possible to define const
instances and save some RAM space by placing those definitions entirely
in ROM.

Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>
2 files changed