Fix: sessiond: missing include causes multiple conflicting definitions

Fix: sessiond: missing include causes multiple conflicting definitions

clang-tidy reports that
/root/lttng-tools/src/bin/lttng-sessiond/ust-ctl-internal.hpp:346:3: error: redefinition of 'LTTNG_PACKED' with a different type: 'struct lttng_ust_ctl_integer_type' vs 'struct lttng_ust_ctl_consumer_channel_attr' [clang-diagnostic-error]
  346 | } LTTNG_PACKED;

Indeed, that header is missing macros.hpp causing LTTNG_PACKED
to be misinterpreted.

Change-Id: I9a0ec916e7ad1c4d926f4d9a33dd6a85fb5b809c
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>