hidl-gen: accept oneway methods

b/30843534: oneway methods seem broken

Change-Id: I122fc26b4054eb0952d209e6b8c18d3a2ea446df
Signed-off-by: Iliyan Malchev <malchev@google.com>
diff --git a/hidl-gen_l.ll b/hidl-gen_l.ll
index 359c351..d2066a9 100644
--- a/hidl-gen_l.ll
+++ b/hidl-gen_l.ll
@@ -61,6 +61,7 @@
 "typedef"		{ count(yyg); return(TYPEDEF); }
 "union"			{ count(yyg); return(UNION); }
 "vec"			{ count(yyg); return(VEC); }
+"oneway"		{ count(yyg); return(ONEWAY); }
 
 "char"			{ SCALAR_TYPE(KIND_CHAR); }
 "bool"			{ SCALAR_TYPE(KIND_BOOL); }