package: libffi: Fix for wrong libffi.pc content in host build

This would also contain 'prefix=/usr'. Not sure what this 'auto'
HOST_STYLE is supposed to do, but in this case it breaks things.

Signed-off-by: Phil Sutter <phil@nwl.cc>

package/libffi/Makefile

@@ -22,7 +22,6 @@ include ${ADK_TOPDIR}/mk/package.mk
 $(eval $(call HOST_template,LIBFFI,libffi,${PKG_VERSION}-${PKG_RELEASE}))
 $(eval $(call PKG_template,LIBFFI,libffi,${PKG_VERSION}-${PKG_RELEASE},${PKG_DEPENDS},${PKG_DESCR},${PKG_SECTION},${PKG_OPTS}))
 
-HOST_STYLE:=		auto
 HOST_CONFIGURE_ARGS+=	--disable-builddir --with-pic --disable-symvers
 CONFIGURE_ARGS+=	--disable-builddir --with-pic --disable-symvers