Switch to NASM for libjpeg_turbo.

Bug: 766721
Change-Id: I436767e68406d557db3c3e85dcf65ad32c41f59a
diff --git a/BUILD.gn b/BUILD.gn
index e3437da..f1fe413 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -24,9 +24,9 @@
 }
 
 if (current_cpu == "x86" || current_cpu == "x64") {
-  import("//third_party/yasm/yasm_assemble.gni")
+  import("//third_party/nasm/nasm_assemble.gni")
 
-  yasm_assemble("simd_asm") {
+  nasm_assemble("simd_asm") {
     defines = []
     include_dirs = [ "simd/nasm/" ]