fvp-docker-images/builders.sh: fix for-loop iteration issue

Removed unnecessary double quotes around the variable
in the for-loop. Quoting caused the loop to treat
the entire string as a single item, preventing correct
iteration over individual file names.

Signed-off-by: Arthur She <arthur.she@linaro.org>
Change-Id: I4be827893242181503936733b5e28cf031d6dff1
1 file changed