busybox: update to 1.31.0

* Update busybox to version 1.31.0.
    New applets: ts, i2ctransfer
    New (restored) feature: error/info levels in syslog messages.
    Leave new features disabled by default.
* Refresh patches
* Remove patch that was backported from upstream

Config refreshed with commands below, after which the OpenWrt specific
config defaults (ipv6, login session child) were corrected:

  make package/busybox/compile   (to populate the build_dir)

  cd package/utils/busybox/config/
  ../convert_menuconfig.pl ../../../../build_dir/target-mips_24kc_musl/busybox-1.31.0

  cd package/utils/busybox
  ./convert_defaults.pl < ../../../build_dir/target-mips_24kc_musl/busybox-1.31.0/.config > Config-defaults.in

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>

package/utils/busybox/config/coreutils/Config.in

@@ -131,7 +131,7 @@ config BUSYBOX_CONFIG_FEATURE_DATE_COMPAT
 	date -s (and other commands like touch -d) use more sensible
 	formats (for one, ISO format YYYY-MM-DD hh:mm:ss.ssssss).
 
-	With this option off, 'date DATE' is 'date -s DATE' support
+	With this option off, 'date DATE' and 'date -s DATE' support
 	the same format. With it on, 'date DATE' additionally supports
 	MMDDhhmm[[YY]YY][.ss] format.
 config BUSYBOX_CONFIG_DD
@@ -282,11 +282,6 @@ config BUSYBOX_CONFIG_FOLD
 	default BUSYBOX_DEFAULT_FOLD
 	help
 	Wrap text to fit a specific width.
-config BUSYBOX_CONFIG_FSYNC
-	bool "fsync (3.6 kb)"
-	default BUSYBOX_DEFAULT_FSYNC
-	help
-	fsync is used to flush file-related cached blocks to disk.
 config BUSYBOX_CONFIG_HEAD
 	bool "head (3.8 kb)"
 	default BUSYBOX_DEFAULT_HEAD
@@ -667,6 +662,11 @@ config BUSYBOX_CONFIG_FEATURE_SYNC_FANCY
 	help
 	sync -d FILE... executes fdatasync() on each FILE.
 	sync -f FILE... executes syncfs() on each FILE.
+config BUSYBOX_CONFIG_FSYNC
+	bool "fsync (3.6 kb)"
+	default BUSYBOX_DEFAULT_FSYNC
+	help
+	fsync is used to flush file-related cached blocks to disk.
 config BUSYBOX_CONFIG_TAC
 	bool "tac (3.9 kb)"
 	default BUSYBOX_DEFAULT_TAC