mtd: spi-nor: gigadevice: gd25q256: Init flash based on SFDP

Get rid of the static initialization of the flash parameters and
init them when parsing SFDP.
Generated a 256 Kbyte random data and did an erase, write, read back
and compare test. The flash uses for reads SPINOR_OP_READ_1_4_4_4B 0xec,
for erases SPINOR_OP_BE_4K_4B 0x21, and for writes SPINOR_OP_PP_1_1_4_4B
0x34.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211207140254.87681-14-tudor.ambarus@microchip.com

drivers/mtd/spi-nor/gigadevice.c

@@ -53,8 +53,8 @@ static const struct flash_info gigadevice_parts[] = {
 		NO_SFDP_FLAGS(SECT_4K | SPI_NOR_DUAL_READ |
 			      SPI_NOR_QUAD_READ) },
 	{ "gd25q256", INFO(0xc84019, 0, 64 * 1024, 512)
+		PARSE_SFDP
 		FLAGS(SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB | SPI_NOR_TB_SR_BIT6)
-		NO_SFDP_FLAGS(SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)
 		FIXUP_FLAGS(SPI_NOR_4B_OPCODES)
 		.fixups = &gd25q256_fixups },
 };