preinit: remove no-longer-used mips assembly

pkgs/preinit/preinit.c

@@ -39,9 +39,6 @@ char buf[COMMAND_LINE_SIZE];
 
 int main(int argc, char *argv[], char *envp[])
 {
-#ifndef PREINIT_USE_LIBC
-        asm("la $gp, _gp\nsw $gp,16($sp)");
-#endif	
 	char *rootdevice = 0;
 	char *p = buf;
 	write(1, banner, strlen(banner));