Release v3.8-alpha7

v3.8-alpha6 release

v3.8-alpha5 release

v3.8 alpha4 release

Add tag: v3.8-alpha3

add tag: v3.8-alpha2

v3.8 aplpha1 release

Tag: v3.7.2 release

rc2 for release process tests

driver: nandflash: make code more tight

As the nand flash id can share with at91sam9260ek,
so no need repeat them for at91sam9260ek.

Signed-off-by: Bo Shen <voice.shen@atmel.com>