package/libwebsock: fix incorrect inline function

Fixes:
    http://autobuild.buildroot.org/results/c02/c0243afc26202cbea98a1a75ddb9e37d8e2e08de/
    http://autobuild.buildroot.org/results/8a0/8a0f34da29fdfb2807aaa7280759e324a3874851/
    http://autobuild.buildroot.org/results/3da/3dac7b3504349e06c05fa0170a033e7828a9ab55/



Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>