mtd: spinand: Fix display of unknown raw ID

mtd: spinand: Fix display of unknown raw ID

In case ID is not found in manufacturer table, the raw ID is
printed using %*phN format which is not supported by lib/vsprintf.c.
The information displayed doesn't reflect the raw ID return by the
unknown spi-nand.

Use %02x format instead, as done in spi-nor-core.c.

For example, before this patch:
  ERROR: spi-nand: spi_nand flash@0: unknown raw ID f74ec040
after
  ERROR: spi-nand: spi_nand flash@0: unknown raw ID 00 c2 26 03

Fixes: 0a6d6bae0386 ("mtd: nand: Add core infrastructure to support SPI NANDs")
Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Acked-by: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>