arm64: dts: mt7986: increase bl2 partition on NAND of Bananapi R3

arm64: dts: mt7986: increase bl2 partition on NAND of Bananapi R3

The bootrom burned into the MT7986 SoC will try multiple locations on
the SPI-NAND flash to load bl2 in case the bl2 image located at the the
previously attempted offset is corrupt.

Use 0x100000 instead of 0x80000 as partition size for bl2 on SPI-NAND,
allowing for up to four redundant copies of bl2 (typically sized a
bit less than 0x40000).

Fixes: 8e01fb15b8157 ("arm64: dts: mt7986: add Bananapi R3")
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://lore.kernel.org/r/ZH9UGF99RgzrHZ88@makrotopia.org
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>