staging: android: ion: Fix unnecessary initialization of static variable

Fix checkpatch warning: removed unnecessary initialization of
static variable "heap_id" to 0 in source file "ioc.c".

Signed-off-by: Fabrizio Perria <fabrizio.perria@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>