Currently, USB Host unit tests that require a software triggered disconnection/
reconnection rely on the 'usb_phy_action()' function.
This commit replaces those calls with 'hcd_port_command()' or
'usb_host_lib_set_root_port_power()'.
Note: Also removed 'test_usb_common.h/c' as it is no longer necessary are the
function call replacements.
Previously, descriptors of the test devices were stored direclty in the mock
device files (e.g., "mock_[hid|msc].[h|c]"). This commit splits out the device
descriptors to separate files (e.g., "dev_[hid|msc].c") along with getter
functions.
Users that want to run the tests locally on a different device simply need to
update the "dev_[hid|msc].c" file for their device.
