remove stray .end directives from powerpc[64] asm

maintainer's note: these are not meaningful/correct/needed and the
clang integrated assembler errors out upon seeing them.

src/ldso/powerpc/dlsym.s

@@ -5,5 +5,4 @@
 dlsym:
 	mflr    5                      # The return address is arg3.
 	b       __dlsym
-	.end    dlsym
 	.size   dlsym, .-dlsym

src/ldso/powerpc64/dlsym.s

@@ -8,5 +8,4 @@ dlsym:
 	.localentry dlsym,.-dlsym
 	mflr    5                      # The return address is arg3.
 	b       __dlsym
-	.end    dlsym
 	.size   dlsym, .-dlsym