generic: Add/rename patches for upstream consistency

ipq40xx: generic-level patch replaces same-source patches-4.19/
         082-v4.20-mtd-spinand-winbond-Add-support-for-W25N01GV.patch

The SPI-NAND framework from Linux uses common driver code that is then
"tuned" by a tiny struct of chip-specific data that describes
available commands, timing, and layout (data and OOB data). Several
manufacturers and chips have been added since 4.19, several of which
are used in devices already supported by OpenWrt (typically with no or
"legacy" access to their NAND memory). This commit catches up the
supported-chip definitions through Linux 5.2-rc6 and linux/next.

The driver is only compiled for platforms with CONFIG_MTD_SPI_NAND=y.
This presently includes ipq40xx and pistachio, with the addition of
ath79-nand in these commits (and not ath79-generic or ath79-tiny).

Upstream patches refreshed against 4.19.75

Build-tested-on: ipq40xx
Run-tested-on: ath79-nand

Signed-off-by: Jeff Kletsky <git-commits@allycomm.com>