toolchain/musl: fix typo on configuration symbol

Signed-off-by: Florian Fainelli <florian@openwrt.org>

SVN-Revision: 34596

toolchain/musl/Config.in

@@ -3,7 +3,7 @@
 choice
 	prompt "musl Version"
 	depends on TOOLCHAINOPTS && USE_MUSL
-	default UCLIBC_VERSION_0_9_7
+	default MUSL_VERSION_0_9_7
 	help
 	  Select the version of musl you wish to use.