Revert "uClibc-ng: update to 1.0.21"

This reverts commit dde5c729ec.

The uClibc update was completely untested, does not build with Kernel 4.4 and
did not adjust the configuration to predeclare new config symbols.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

toolchain/uClibc/Config.version

@@ -1,7 +1,7 @@
 config UCLIBC_VERSION
 	string
 	depends on USE_UCLIBC
-	default "1.0.21"
+	default "1.0.14"
 
 config UCLIBC_VERSION_NG
 	bool

toolchain/uClibc/common.mk

@@ -16,7 +16,7 @@ CONFIG_DIR:=$(PATH_PREFIX)/config
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 LIBC_SO_VERSION:=$(PKG_VERSION)
 
-PKG_HASH:=6e99ebebe8a46ddcd26615828d51b62dbf580568aa58bf5f495da37eba0c872d
+PKG_HASH:=3c63d9f8c8b98b65fa5c4040d1c8ab1b36e99a16e1093810cedad51ac15c9a9e
 
 HOST_BUILD_DIR:=$(BUILD_DIR_TOOLCHAIN)/$(PKG_NAME)-$(PKG_VERSION)