trace-cmd documentation: Remove check-manpages.sh for trace-cmd in meson build

The creation of man pages for trace-cmd ran the check-manpages.sh script,
which is only used for the libtracecmd library, not the tools. This caused
the build to spit out warning of grep not finding libtracecmd.txt.

Link: https://lore.kernel.org/linux-trace-devel/20240725112620.17c6d1b2@gandalf.local.home

Cc: Daniel Wagner <wagi@monom.org>
Fixes: 736df0648d16b ("trace-cmd: Add initial support for meson")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>