Update syscall-names.list for Linux 4.20.

This patch updates sysdeps/unix/sysv/linux/syscall-names.list for
Linux 4.20.  Although there are no new syscalls, the
riscv_flush_icache syscall has moved to asm/unistd.h (previously in
asm/syscalls.h) and so now needs to be added to the list.

Tested with build-many-glibcs.py.

	* sysdeps/unix/sysv/linux/syscall-names.list: Update kernel
	version to 4.20.
	(riscv_flush_icache): New syscall.

(cherry picked from commit 47ad5e1a2a3ab8eeda491454cbef3b1c5239dc02)

diff --git a/ChangeLog b/ChangeLog
index 30a5bed6b09efcef..0f4f95193ff07d45 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2019-01-01  Joseph Myers  <joseph@codesourcery.com>
+
+	* sysdeps/unix/sysv/linux/syscall-names.list: Update kernel
+	version to 4.20.
+	(riscv_flush_icache): New syscall.
+
 2018-10-22  Joseph Myers  <joseph@codesourcery.com>
 
 	* sysdeps/unix/sysv/linux/syscall-names.list: Update kernel
diff --git a/sysdeps/unix/sysv/linux/syscall-names.list b/sysdeps/unix/sysv/linux/syscall-names.list
index f88001c9c38d5fc7..d623dc1d9af027be 100644
--- a/sysdeps/unix/sysv/linux/syscall-names.list
+++ b/sysdeps/unix/sysv/linux/syscall-names.list
@@ -22,8 +22,8 @@
 # names are only used if the installed kernel headers also provide
 # them.
 
-# The list of system calls is current as of Linux 4.19.
-kernel 4.19
+# The list of system calls is current as of Linux 4.20.
+kernel 4.20
 
 FAST_atomic_update
 FAST_cmpxchg
@@ -431,6 +431,7 @@ renameat
 renameat2
 request_key
 restart_syscall
+riscv_flush_icache
 rmdir
 rseq
 rt_sigaction