QSPI Boot source support Overview
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	1. LS1043A
		LS1043AQDS
	2. LS2080A
		LS2080AQDS
	3. LS1012A
		LS1012AQDS
		LS1012ARDB
	4. LS1046A
		LS1046AQDS
		LS1046ARDB

Booting from QSPI
-------------------
Booting from QSPI requires two images, RCW and u-boot-dtb.bin.
The difference between QSPI boot RCW image and NOR boot image is the PBI
command sequence for setting the boot location pointer. It's should point
to the address for u-boot in QSPI flash.

RCW image should be written to the beginning of QSPI flash device.
Example of using u-boot command

=> sf probe 0:0
SF: Detected S25FL256S_64K with page size 256 Bytes, erase size 64 KiB, total 32 MiB
=> sf erase 0 +<size of rcw image>
SF: 65536 bytes @ 0x0 Erased: OK
=> sf write <rcw image in memory> 0 <size of rcw image>
SF: 164 bytes @ 0x0 Written: OK

To get the QSPI image, build u-boot with QSPI config, for example,
<board_name>_qspi_defconfig. The image needed is u-boot-dtb.bin.
The u-boot image should be written to 0x10000(but 0x1000 for LS1043A, LS2080A).

=> sf probe 0:0
SF: Detected S25FL256S_64K with page size 256 Bytes, erase size 64 KiB, total 32 MiB
=> sf erase 10000 +<size of u-boot image>
SF: 589824 bytes @ 0x10000 Erased: OK
=> sf write <u-boot image in memory> 10000 <size of u-boot image>
SF: 580966 bytes @ 0x10000 Written: OK

With these two images in QSPI flash device, the board can boot from QSPI.