powerpc/bpf: Remove bpf_jit_free()

Commit 74451e66 ("bpf: make jited programs visible in traces") added
a default bpf_jit_free() implementation. Powerpc did not use the default
bpf_jit_free() as powerpc did not set the images read-only. The default
bpf_jit_free() called bpf_jit_binary_unlock_ro() is why it could not be
used for powerpc.

Commit d53d2f78 ("bpf: Use vmalloc special flag") moved keeping
track of read-only memory to vmalloc. This included removing
bpf_jit_binary_unlock_ro(). Therefore there is no reason powerpc needs
its own bpf_jit_free(). Remove it.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210609013431.9805-6-jniethe5@gmail.com

arch/powerpc/net/bpf_jit_comp.c

@@ -257,15 +257,3 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
 
 	return fp;
 }
-
-/* Overriding bpf_jit_free() as we don't set images read-only. */
-void bpf_jit_free(struct bpf_prog *fp)
-{
-	unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
-	struct bpf_binary_header *bpf_hdr = (void *)addr;
-
-	if (fp->jited)
-		bpf_jit_binary_free(bpf_hdr);
-
-	bpf_prog_unlock_free(fp);
-}