This patch changes the cword union to use specific length types that are
architecture indepented.

This patch also renames the members of the cword union to represent
their usage, i.e.:

    c  -> w8
    s  -> w16
    l  -> w32
    ll -> w64

Where "w" stands for "width" in bits.

I discovered this problem when enabling CFI flash on vexpress64.
cword.l was an unsigned long int, but it was intended to be 32 bits wide.
Unfortunately, it's 64-bits wide on a 64-bit system, meaning that a
64-bit system fails when attempting to use 32-bit wide CFI flash parts.

Similar problems also existed with the other cword sizes.

Signed-off-by: Ryan Harkin <ryan.harkin@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Stefan Roese <sr@denx.de>