[FIX] Avoid compiler error with Altera Nios using obdcdc.c

Note that obdcdc.c is currently used with Altera Nios II MN without any
file system, hence, this fix only avoids compiler errors!

Change-Id: Iabb83dedf0e5639ed56b0c4c58f883e4945e4133
Reviewed-on: http://brateggevoat1/gerrit/565
Tested-by: Jenkins <jenkins@brateggevoat1.br-automation.co.at>
Reviewed-by: Josef Baumgartner <josef.baumgartner@br-automation.com>
[TASK] Add Nios II target implementation for platforms without Shared Buffer

Change-Id: I72e055a7520d4280d817d8c605eb303f5eb688d9
Reviewed-on: http://brateggevoat1/gerrit/563
Tested-by: Jenkins <jenkins@brateggevoat1.br-automation.co.at>
Reviewed-by: Josef Baumgartner <josef.baumgartner@br-automation.com>
[TASK] Add Nios II console IO primitives

Change-Id: I50f940601be5a024c5348c1a1116720e682badce
Reviewed-on: http://brateggevoat1/gerrit/564
Tested-by: Jenkins <jenkins@brateggevoat1.br-automation.co.at>
Reviewed-by: Josef Baumgartner <josef.baumgartner@br-automation.com>
[TASK] Adapt doxygen file to new directory structure

Change-Id: I5a24842c2df3e8f8f15d5c9165c3e69f041d387d
Reviewed-on: http://brateggevoat1/gerrit/566
Tested-by: Jenkins <jenkins@brateggevoat1.br-automation.co.at>
Reviewed-by: Josef Baumgartner <josef.baumgartner@br-automation.com>