linker benchmark: our riscv64 toolchain has lga now.

This doesn't make any difference, but it does let us delete an obsolete comment.

Change-Id: Ibf81978bb7883e8c6b86c1f6c459ff70bca3f682
diff --git a/benchmarks/linker_relocation/include/linker_reloc_bench_asm.h b/benchmarks/linker_relocation/include/linker_reloc_bench_asm.h
index 885e47f..ea63e36 100644
--- a/benchmarks/linker_relocation/include/linker_reloc_bench_asm.h
+++ b/benchmarks/linker_relocation/include/linker_reloc_bench_asm.h
@@ -44,9 +44,7 @@
 
 #elif defined(__riscv)
 
-// No `lga` in clang unless https://reviews.llvm.org/D107278 lands.
-// `la` is equivalent when using PIC (which we do) though.
-#define GOT_RELOC(sym) la a0, sym
+#define GOT_RELOC(sym) lga a0, sym
 #define CALL(sym) call sym@plt
 #define DATA_WORD(val) .quad val
 #define MAIN .globl main; main: li a0, 0; ret