buildroot

poppler: bump version to 0.55.0

--enable-libjpeg option is now --enable-dctdecoder=libjpeg, and
--disable-libjpeg is now --enable-dctdecoder=none. See this upstream
commit:
  https://cgit.freedesktop.org/poppler/poppler/commit/?id=b286a6b5b1a63563263072305da04604cb022488

Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>