add -L to generate little-endian code.

Reference: /n/sources/patch/applied/va-little
Date: Sat Mar 25 03:30:40 CET 2006
Signed-off-by: geoff@collyer.net

--- /sys/src/cmd/va/lex.c	Sat Mar 25 03:30:28 2006
+++ /sys/src/cmd/va/lex.c	Sat Mar 25 03:30:24 2006
@@ -36,6 +36,10 @@
 		p = ARGF();
 		setinclude(p);
 		break;
+	case  'L':			/* for little-endian mips */
+		thechar = '0';
+		thestring = "spim";
+		break;
 	} ARGEND
 	if(*argv == 0) {
 		print("usage: %ca [-options] file.s\n", thechar);