multimedia/dav1d: unbreak with LLD on i386

ld: error: can't create dynamic relocation R_386_32 against local symbol in readonly segment; recompile object files with -fPIC or pass '-Wl,-z,notext' to allow text relocations in the output

defined in src/25a6634@@dav1d@sha/mc_ssse3.obj
referenced by ../src/x86/mc_ssse3.asm

src/25a6634@@dav1d@sha/mc_ssse3.obj:(.text+0x16)

Reported by: antoine (via emaste, bug 214864 exp-run)