misc: cardreader: add new Alcor Micro Cardreader PCI driver

misc: cardreader: add new Alcor Micro Cardreader PCI driver

This driver provides support for Alcor Micro AU6601 and AU6621
card readers.

This is single LUN HW and it is expected to work with following standards:
- Support SDR104 / SDR50
- MultiMedia Card (MMC)
- Memory Stick (MS)
- Memory Stick PRO (MS_Pro)

Since it is a PCIe controller, it should work on any architecture
supporting PCIe. For now, it was developed and tested only on x86_64.

This driver is a result of RE work and was created without any
documentation or real knowledge of HW internals.

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>