PCM051LB: Add support for Cosmic-AM335x

Signed-off-by: Nitesh Chowdhary <nitesh.c@phytec.in>
PCM051LB: change default boot mode to nand

Signed-off-by: Nitesh Chowdhary <nitesh.c@easyarm.com>
PCM051LB: Add update command in defaultenv-2

Signed-off-by: Nitesh Chowdhary <nitesh.c@phytec.in>
PCM051LB: 3.5 inch LCD support

Signed-off-by: Nitesh Chowdhary <nitesh.c@phytec.in>