linux-user: support SO_{SND, RCV}BUFFORCE setsockopt options

Translate the SO_SNDBUFFORCE & SO_RCVBUFFORCE options to setsockopt to
the host values & perform the syscall as expected, allowing use of those
options by target programs.

Signed-off-by: Paul Burton <paul@archlinuxmips.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index b1e57df..bdc60fe 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -1502,9 +1502,15 @@
         case TARGET_SO_SNDBUF:
 		optname = SO_SNDBUF;
 		break;
+        case TARGET_SO_SNDBUFFORCE:
+                optname = SO_SNDBUFFORCE;
+                break;
         case TARGET_SO_RCVBUF:
 		optname = SO_RCVBUF;
 		break;
+        case TARGET_SO_RCVBUFFORCE:
+                optname = SO_RCVBUFFORCE;
+                break;
         case TARGET_SO_KEEPALIVE:
 		optname = SO_KEEPALIVE;
 		break;