gmp: use same source tarball for tools/gmp and package/libs/gmp

tools/gmp was using the .tar.xz while package/libs/gmp was using the
.tar.gz archive of the GMP release. Use the .tar.gz for both of them.

Signed-off-by: Daniel Golle <[email protected]>

package/libs/gmp/Makefile

@@ -11,9 +11,9 @@ PKG_NAME:=gmp
 PKG_VERSION:=6.3.0
 PKG_RELEASE:=1
 
-PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION)$(PKG_REVISION).tar.xz
+PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=@GNU/gmp/
-PKG_HASH:=a3c2b80201b89e68616f4ad30bc66aee4927c3ce50e33929ca819d5c43538898
+PKG_HASH:=e56fd59d76810932a0555aa15a14b61c16bed66110d3c75cc2ac49ddaa9ab24c
 
 PKG_BUILD_PARALLEL:=1
 PKG_INSTALL:=1