Revert "pkg/debian: Statically link libc for sign-file"

This reverts commit c7d4b132980589075e8cb9ac5e2d3759e7958ce0.

Adding -lc breaks the final sign-file binary.

pkg/debian/kernel/0001-kbuild-Link-sign-file-statically.patch

@@ -16,7 +16,7 @@ index bc90520a54266..1d092bfd28e3a 100644
  HOSTCFLAGS_asn1_compiler.o = -I$(srctree)/include
  HOSTCFLAGS_sign-file.o = $(shell $(HOSTPKG_CONFIG) --cflags libcrypto 2> /dev/null)
 -HOSTLDLIBS_sign-file = $(shell $(HOSTPKG_CONFIG) --libs libcrypto 2> /dev/null || echo -lcrypto)
-+HOSTLDLIBS_sign-file = -Wl,-Bstatic -lc $(shell $(HOSTPKG_CONFIG) --static --libs libcrypto 2> /dev/null || echo -lcrypto -ldl -pthread) -Wl,-Bdynamic
++HOSTLDLIBS_sign-file = -Wl,-Bstatic $(shell $(HOSTPKG_CONFIG) --static --libs libcrypto 2> /dev/null || echo -lcrypto -ldl -pthread) -Wl,-Bdynamic
  
  ifdef CONFIG_UNWINDER_ORC
  ifeq ($(ARCH),x86_64)