mtd: spi-nor: spansion: Use nor->addr_nbytes in octal DTR mode in RD_ANY_REG_OP

mtd: spi-nor: spansion: Use nor->addr_nbytes in octal DTR mode in RD_ANY_REG_OP

In octal DTR mode, RD_ANY_REG_OP needs to use 4-byte address regardless
of flash's internal address mode. Use nor->addr_nbytes which is set to 4
during setup.

Fixes: eff9604390d6 ("mtd: spi-nor: spansion: add octal DTR support in RD_ANY_REG_OP")
Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
Link: https://lore.kernel.org/r/20241016000837.17951-1-Takahiro.Kuwano@infineon.com
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>