of: reserved_mem: Use proper binary prefix

The printed reserved memory information uses the non-standard "K"
prefix, while all other printed values use proper binary prefixes.
Fix this by using "Ki" instead.

While at it, drop the superfluous spaces inside the parentheses, to
reduce printed line length.

Fixes: aeb9267e ("of: reserved-mem: print out reserved-mem details during boot")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230216083725.1244817-1-geert+renesas@glider.be


Signed-off-by: Rob Herring <robh@kernel.org>