mtd: spi-nor: Add MT25U01G part number for SPI NOR Flash

MT25QU01 OPN with 4B OPCODE support is currently not supported in
source code and the driver reuses the definition for "n25q00a"
which has the same silicon ID but is a slower part.

Adding mt25u01g definition to the source code to support a faster
read response for MT25QU01 QSPI NOR Flash device.

Signed-off-by: Jit Loon Lim <jit.loon.lim@intel.com>
[jagan: fix the id position and commit head]
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>