libgphoto2 has OOB read in ptp_unpack_Sony_DPD() FormFlag parsing in ptp-pack.c

libgphoto2 is a camera access and control library. Versions up to and including 2.5.33 have an out-of-bounds read in `ptp_unpack_Sony_DPD()` in `camlibs/ptp2/ptp-pack.c` (line 842). The function reads the FormFlag byte via `dtoh8o(data, *poffset)` without a prior bounds check. The standard `ptp_unpack_DPD()` at lines 686–687 correctly validates `*offset + sizeof(uint8_t) > dpdlen` before this same read, but the Sony variant omits this check entirely. Commit 09f8a940b1e418b5693f5c11e3016a1ad2cea62d fixes the issue.