RemoteLinux: Simplify default deploy step widget summary text.

Including the device configuration name might not be grammatically
correct in all cases. Also might not be consistent with deploy steps
not inheriting from AbstractRemoteLinuxDeployStep. So let's just take
the step's display name as-is.

Change-Id: I953ee1eb7314dec3dbe4ea39f8370186f3d282c1
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@nokia.com>