mtd: nand: Add qpic_common API file

Add qpic_common.c file which hold all the common
qpic APIs which will be used by both qpic raw nand
driver and qpic spi nand driver.

Signed-off-by: Md Sadre Alam <quic_mdalam@quicinc.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>