MdeModulePkg/Usb/EfiKey: Fix endpoint selection

MdeModulePkg/Usb/EfiKey: Fix endpoint selection

The endpoint selected by the driver needs to not
only be an interrupt type, but have direction IN
as required to set up an asynchronous interrupt transfer.

Currently, the driver assumes that the first INT endpoint
will be of type IN, but that is not true of all devices,
and will silently fail on devices which have the OUT endpoint
before the IN. Adjust the endpoint selection loop to explictly
check for direction IN.

Test: detachable keyboard on Google Pixel Slate now works.

Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-by: GuoMinJ <newexplorerj@gmail.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>