libwebsockets

CMakeLists.txt: fix build with libev and without testapps

Move libev workaround outside the
if ((LWS_ROLE_H1 OR LWS_ROLE_H2) AND NOT LWS_WITHOUT_TESTAPPS) block
otherwise build fails on:

/home/naourr/work/instance-1/output-1/build/libwebsockets-3.2.0/lib/event-libs/libev/libev.c: In function 'lws_ev_hrtimer_cb':
/home/naourr/work/instance-1/output-1/build/libwebsockets-3.2.0/lib/event-libs/libev/libev.c:34:3: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
   ev_timer_set(&pt->ev.hrtimer, ((float)us) / 1000000.0, 0);
   ^~~~~~~~~~~~

Fixes:
 - http://autobuild.buildroot.org/results/b5a2188dce90f3ca9bf0cc7a043c1a946b8e288f

AG: this doesn't really fix anything... the spew is intentionally part of libev.
    It just hides the spew... since the maintainer won't fix it
    this is the only way AFAIK.  Other than don't use libev.

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>