x86/platform/iosf_mbi: Remove duplicate definitions

The read and write opcodes are global for all units on SoC and even across
Intel SoCs. Remove duplication of corresponding constants. At the same time
convert all current users.

No functional change.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Boon Leong Ong <boon.leong.ong@intel.com>
Acked-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>