nand/tcl: pass CMD to nand_list_walker()

nand/tcl: pass CMD to nand_list_walker()

To prepare for handling TCL return values consistently, all calls
to command_print/command_print_sameline should be ready to switch
to CMD as first parameter.

Pass CMD instead of CMD_CTX as parameter to nand_list_walker().

This change was part of http://openocd.zylin.com/1815 from Paul
Fertser and has been extracted and rebased to simplify the review.

Change-Id: Ia11887dfc6dc58d5458a88ba84780cd895b8c253
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5053
Tested-by: jenkins