staging: r8188eu: fix the number of probereq retries

staging: r8188eu: fix the number of probereq retries

issue_probereq_ex sends a probe request and retries if this fails. There's
no point in making the number of retries configurable. Hard-code the value
that's used by issue_probereq_ex's only caller.

Simplify the code to check the loop condition only once.

Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20221126154253.178275-4-martin@kaiser.cx
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>