spi.h: Rename the spi.h to spi-generic.h

Since there are and will be other files in nb/sb folders, we change
the general spi.h to a file name which is not easy to be duplicated.

Change-Id: I6548a81206caa608369be044747bde31e2b08d1a
Signed-off-by: Zheng Bao <zheng.bao@amd.com>
Signed-off-by: zbao <fishbaozi@gmail.com>
Reviewed-on: http://review.coreboot.org/2309
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
11 files changed