mtd: cfi: Fix checking status register feature

mtd: cfi: Fix checking status register feature

Commit 72443c7f7d21 ("mtd: cfi: Add support for status register
polling") added a feature check to determine if status register
is available for certain flash chips. The "lower software bits"
register used to determine this feature is not backward compati-
ble. Older flash chips without this feature has reserved value
0xff. Instead of checking "lower software bits" register, use
CFI primary vendor-specific extended query. Since CFI version
1.4, software features can be read from offset 0x53 according to
document AN201168 from Cypress.

Signed-off-by: York Sun <[email protected]>
CC: Marek Vasut <[email protected]>
Tested-by: Marek Vasut <[email protected]>
Signed-off-by: Stefan Roese <[email protected]>