SPI-NOR framework is based on SPI-MEM framework using
spi_mem_op execution interface.

It implements read functions and allows NOR configuration
up to quad mode.
Default management is 1 data line but it can be overridden
by platform.
It also includes specific quad mode configuration for
Spansion, Micron and Macronix memories.

Change-Id: If49502b899b4a75f6ebc3190f6bde1013651197f
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Signed-off-by: Christophe Kerello <christophe.kerello@st.com>