arm: mx6: cm_fx6: expand boot sequence

Expand boot sequence to the following order:
1) mmc boot: mmc boot script, then mmc bootm, then mmc bootz.
2) usb boot: usb boot script.
3) sata boot: sata boot script, sata bootm, sata bootz.
4) nand boot: nand bootm, then nand bootz.

Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
arm: mx6: cm_fx6: change issd gpio order

Change the order in which GPIOs are toggled in SATA init sequence to
accomodate both SanDisk and Phison SSDs.

Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
arm: mx6: cm_fx6: detect 1GB DRAM correctly on solo

The 1GB DRAM configuration on mx6 solo uses 2 chip selects, but
the code tests 1GB DRAM configuration as if it is all present on one
chip select, and thus cannot see the full range of available memory.

Refactor the check to detect 1GB DRAM correctly.

Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
arm: mx6: cm_fx6: tag u-boot version -cm-fx6-1.3

Tag U-Boot version -cm-fx6-1.3
This is a bug fix release.

Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>