cmake: dereference ${check} after zephyr_check_compiler_flag() call

Follow-up: #53124

The PR#53124 fixed an issue where the variable `check` was not properly
dereferenced into the correct variable name for return value storage.
This was corrected in 04a27651.

However, some code was passing a return argument as:
`zephyr_check_compiler_flag(... ${check})`
but checking the result like:
`if(${check})`
thus relying on a faulty behavior of code updating `check` and not the
`${check}` variable.

Fix this by updating to use `${${check}}` as that will point to the
correct return value.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
(cherry picked from commit 45b25e55)