modpost: free allocated memory

valgrind complains that memory is not freed after allocation
with realloc() called from main() and write_dump().

So let us free the allocated memory properly.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Link: http://lkml.kernel.org/r/1470166981-6461-1-git-send-email-xypron.glpk@gmx.deSigned-off-by: Jessica Yu <jeyu@redhat.com>

scripts/mod/modpost.c

@@ -2371,6 +2371,7 @@ static void write_dump(const char *fname)
 		}
 	}
 	write_if_changed(&buf, fname);
+	free(buf.p);
 }
 
 struct ext_sym_list {
@@ -2496,6 +2497,7 @@ int main(int argc, char **argv)
 			      "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
 		}
 	}
+	free(buf.p);
 
 	return err;
 }