Tiva PHY Interrupts: Need to read the PHY interrupt status register in order to clear the pending PHY interrupt

stm32f429i-disco: change ltdc initializing during boot up. This moves initializing of the ili9341 lcd and ltdc driver to the board specific initializing routine.

Signed-off-by: Marco Krahl <ocram.lhark@gmail.com>

STM32F429i-Disco USB:  Strangeness: Conditioned on OTGHS but called otgfs initialize routines.  Must be something broken

Tiva SSI: Fix some recent breakage to the Tiva SSI driver for the case where only one SSI modules is enabled

Tiva SSI and board configurations: hange negative Tiva logic CONFIG_SSIx_DISABLE to positive logic CONFIG_TIVA_SSIx.  Add support for SSI2 and SSI3

Tiva:  Add a configuration setting to better distinguish TM4C123 and 129 families.  Reanem tm4c_syscontrol.h to tm4c123_syscontrol.h; rename tm4c129x_syscontrol.h to tm4c129_syscontrol.h

STM32 LTDC: Move ltdc.h from include/nuttx/video to arch/arm/include/stm32; Trivial updates after general review