meson: Fix channel command invaild

Fix channel command invaild, `channelcommands.cpp` file is missing in
meson.build.

Tested:

ipmitool channel info 1
Channel 0x1 info:
  Channel Medium Type   : 802.3 LAN
  Channel Protocol Type : IPMB-1.0
  Session Support       : multi-session
  Active Session Count  : 0
  Protocol Vendor ID    : 7154
  Volatile(active) Settings
    Alerting            : enabled
    Per-message Auth    : enabled
    User Level Auth     : enabled
    Access Mode         : always available
  Non-Volatile Settings
    Alerting            : enabled
    Per-message Auth    : enabled
    User Level Auth     : enabled
    Access Mode         : always available

Change-Id: I36436a78b4344087b4d079fa1775383005a0bd3d
Signed-off-by: Jian Zhang <zhangjian.3032@bytedance.com>
diff --git a/meson.build b/meson.build
index 86a50ee..3b15faa 100644
--- a/meson.build
+++ b/meson.build
@@ -220,6 +220,7 @@
   'ipmi_fru_info_area.cpp',
   'read_fru_data.cpp',
   'sensordatahandler.cpp',
+  'user_channel/channelcommands.cpp',
   generated_src,
   transportoem_src,
   conf_h,