ARM: shmobile: bockw-reference dts: Replace "nor-jedec" by "jedec,spi-nor"

Cfr. commit 8947e396 ('Documentation: dt: mtd: replace
"nor-jedec" binding with "jedec, spi-nor"')

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>