dvd_filesystem.h unconditionally uses the glibc LFS64 off64_t name.
musl's off_t is already 64-bit, so typedef it the same way the other
non-glibc branches already do. This also fixes libdvdnav, which
consumes this staged header.
AI-Generated: Uses Claude Code
Signed-off-by: Khem Raj <khem.raj@oss.qualcomm.com>
