libsel4muslcsys: remove duplicate definitions of tkill

libsel4muslcsys/src/sys_stubs.c

diff --git a/libsel4muslcsys/src/sys_stubs.c b/libsel4muslcsys/src/sys_stubs.c
index d7c306a..0fcd7b6 100644
--- a/libsel4muslcsys/src/sys_stubs.c
+++ b/libsel4muslcsys/src/sys_stubs.c
@@ -1170,11 +1170,6 @@
     assert(!"sys_fremovexattr not implemented");
     return 0;
 }
-long sys_tkill(va_list ap)
-{
-    assert(!"sys_tkill not implemented");
-    return 0;
-}
 long sys_sendfile64(va_list ap)
 {
     assert(!"sys_sendfile64 not implemented");
@@ -2640,11 +2635,6 @@
     assert(!"sys_fremovexattr not implemented");
     return 0;
 }
-long sys_tkill(va_list ap)
-{
-    assert(!"sys_tkill not implemented");
-    return 0;
-}
 long sys_sendfile64(va_list ap)
 {
     assert(!"sys_sendfile64 not implemented");