Fix include directories for NASM.

For some reason the -I. isn't working with JPEG turbo.

R=cblume

Bug: 766721
Change-Id: Ifa7fb8034bba6221a4428efe4715bdb29f909a5c
diff --git a/BUILD.gn b/BUILD.gn
index f1fe413..20e95f3 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -31,6 +31,7 @@
     include_dirs = [ "simd/nasm/" ]
 
     if (current_cpu == "x86") {
+      include_dirs += [ "simd/i386/" ]
       sources = [
         "simd/i386/jccolor-avx2.asm",
         "simd/i386/jccolor-mmx.asm",
@@ -82,6 +83,7 @@
         "PIC",
       ]
     } else if (current_cpu == "x64") {
+      include_dirs += [ "simd/x86_64/" ]
       sources = [
         "simd/x86_64/jccolor-avx2.asm",
         "simd/x86_64/jccolor-sse2.asm",