Revert "zoneinfo: Updated to the latest release"

This reverts commit 1f5f599d0e
that bumped the zoneinfo version from 2020a to 2020b.

Apparently some libc are incompatible with the data format in 2020b.
At least our default libc, musl, fails to parse timezones from the
compiled 2020b zoneinfo files.

Release notes mention that deprecated "posixrules" feature is now
omitted from the default build. Possibly musl uses it?

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

utils/zoneinfo/Makefile

@@ -9,7 +9,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=zoneinfo
-PKG_VERSION:=2020b
+PKG_VERSION:=2020a
 PKG_RELEASE:=1
 
 #As i couldn't find real license used "Public Domain"
@@ -19,14 +19,14 @@ PKG_LICENSE:=Public Domain
 PKG_SOURCE:=tzdata$(PKG_VERSION).tar.gz
 PKG_SOURCE_CODE:=tzcode$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=http://www.iana.org/time-zones/repository/releases
-PKG_HASH:=9b053f951d245ce89d850b96ee4711d82d833559b1fc96ba19f90bc4d745e809
+PKG_HASH:=547161eca24d344e0b5f96aff6a76b454da295dc14ed4ca50c2355043fb899a2
 
 include $(INCLUDE_DIR)/package.mk
 
 define Download/tzcode
    FILE=$(PKG_SOURCE_CODE)
    URL=$(PKG_SOURCE_URL)
-   HASH:=47eff8944de4a64f7629b851e4a32338ab12c9b73edd62063795167ff1fe43da
+   HASH:=7d2af7120ee03df71fbca24031ccaf42404752e639196fe93c79a41b38a6d669
 endef
 
 $(eval $(call Download,tzcode))