cmd_ide: enhance new feature "CONFIG_IDE_AHB"

cmd_ide: enhance new feature "CONFIG_IDE_AHB"

Although most IDE controller is designed to be connected to PCI bridge,
there are still some IDE controller support AHB interface for SoC design.

The driver implementation of these IDE-AHB controllers differ from other
IDE-PCI controller, some additional registers and commands access is required
during CMD/DATA I/O. Hence a configuration "CONFIG_IDE_AHB" in cmd_ide.c is
required to be defined to support these kinds of SoC controllers. Such as
Faraday's FTIDE020 series and Global Unichip's UINF-0301.

Signed-off-by: Macpaul Lin <macpaul@andestech.com>