x86/microcode/AMD: Use find_microcode_in_initrd()

Use the generic helper instead of semi-open-coding the procedure.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-11-bp@alien8.de


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>