SPI nor drivers refactor

Moved common SPI flash driver code (device table,
common commands) into flash/nor/spi.c and spi.h.
Updated flash/nor/stmsmi.c to reflect this refactor.

Change-Id: I141644b0af71d3835f29f06dd15b505a00e5b6ec
Signed-off-by: George Harris <george@luminairecoffee.com>
Reviewed-on: http://openocd.zylin.com/782
Tested-by: jenkins
Reviewed-by: Aurelien Jacobs <aurel@gnuage.org>
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>

src/flash/nor/Makefile.am

@@ -22,6 +22,7 @@ NOR_DRIVERS = \
 	non_cfi.c \
 	ocl.c \
 	pic32mx.c \
+	spi.c \
 	stmsmi.c \
 	stellaris.c \
 	stm32f1x.c \
@@ -42,6 +43,7 @@ noinst_HEADERS = \
 	driver.h \
 	imp.h \
 	non_cfi.h \
-	ocl.h
+	ocl.h \
+	spi.h
 
 MAINTAINERCLEANFILES = $(srcdir)/Makefile.in