kernel: Add support for Winbond w25q128jv SPI NOR flash

kernel: Add support for Winbond w25q128jv SPI NOR flash

Newer batches of several Mikrotik boards contain this yet-unsupported
flash chip, for instance:

- rb941-2nd (hAP lite)
- rb952ui-5ac2nd (hAP ac lite)
- RBM33G

and probably other Mikrotik boards need this patch as well.

The patch was submitted upstream by Robert Marko: https://patchwork.ozlabs.org/patch/934181/

Closes: FS#1715
Signed-off-by: Baptiste Jonglez <git@bitsofnetworks.org>
Cc: Robert Marko <robimarko@gmail.com>
[Rebased + refreshed on current kernels]
Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>