package/libwebsockets: needs dynamic library

package/libwebsockets: needs dynamic library

kismets fails to build statically with libwebsockets since commit
14522a8f9d272204763c49a21ebce5653430c612 because libwebsockets does not
specify any Libs.Private field in its pkg-config file resulting in the
following failure:

configure:10659: checking for lws_client_connect_via_info in -lwebsockets
configure:10684: /usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-1/output-1/host/bin/arm-linux-g++ -std=gnu++17 -o conftest -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -O2   -static -static -O3 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 conftest.cpp -lwebsockets  -latomic -lz >&5
/usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-1/output-1/host/opt/ext-toolchain/bin/../lib/gcc/arm-buildroot-linux-uclibcgnueabi/9.3.0/../../../../arm-buildroot-linux-uclibcgnueabi/bin/ld: /usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-1/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libwebsockets.a(tls.c.o): in function `alpn_cb':
tls.c:(.text+0x24): undefined reference to `SSL_select_next_proto'

As it is not trivial to specify Libs.Private with cmake buildsystem
(i.e. LIB_LIST contains the list of libraries but in the "cmake format"
with full paths and ';'), just disable static build with libwebsockets.

Fixes:
 - http://autobuild.buildroot.org/results/9fc7891b61b1c487b95f07c59b802dd98ef71e3a

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>