mtd: cfi_cmdset_0002: fix the check for valid primary extension versions

Valid primary extension versions are: 1.0, 1.1, 1.2, 1.3 [1][2].
Fix the check in cfi_cmdset_0002 accordingly.

[1] http://www.amd.com/us-en/assets/content_type/DownloadableAssets/cfi_r20.pdf, page 19
[2] http://www.amd.com/us-en/assets/content_type/DownloadableAssets/cfi_100_20011201.pdf



Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Guillaume LECERF <glecerf@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>