Support .asm files for assembly

Test: mmma -j external/libjpeg-turbo
Change-Id: Id192dae5d74ecbf500fc668931c37f9b91d25ca4
diff --git a/cc/cc.go b/cc/cc.go
index df4e5cf..a4f8e58 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -101,6 +101,7 @@
 	LdFlags     []string // Flags that apply to linker command lines
 	libFlags    []string // Flags to add libraries early to the link order
 	TidyFlags   []string // Flags that apply to clang-tidy
+	YasmFlags   []string // Flags that apply to yasm assembly source files
 
 	Toolchain config.Toolchain
 	Clang     bool