mtd: spi-nor: issi: is25lp256: 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_4B 0x12.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211207140254.87681-15-tudor.ambarus@microchip.com

drivers/mtd/spi-nor/issi.c

@@ -46,7 +46,7 @@ static const struct flash_info issi_parts[] = {
 	{ "is25lp128",  INFO(0x9d6018, 0, 64 * 1024, 256)
 		NO_SFDP_FLAGS(SECT_4K | SPI_NOR_DUAL_READ) },
 	{ "is25lp256",  INFO(0x9d6019, 0, 64 * 1024, 512)
-		NO_SFDP_FLAGS(SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)
+		PARSE_SFDP
 		FIXUP_FLAGS(SPI_NOR_4B_OPCODES)
 		.fixups = &is25lp256_fixups },
 	{ "is25wp032",  INFO(0x9d7016, 0, 64 * 1024,  64)