wifi: wilc1000: fix ies_len type in connect path

Commit 205c5030 ("wifi: wilc1000: fix RCU usage in connect path")
made sure that the IEs data was manipulated under the relevant RCU section.
Unfortunately, while doing so, the commit brought a faulty implicit cast
from int to u8 on the ies_len variable, making the parsing fail to be
performed correctly if the IEs block is larger than 255 bytes. This failure
can be observed with Access Points appending a lot of IEs TLVs in their
beacon frames (reproduced with a Pixel phone acting as an Access Point,
which brough 273 bytes of IE data in my testing environment).

Fix IEs parsing by removing this undesired implicit cast.

Fixes: 205c5030

 ("wifi: wilc1000: fix RCU usage in connect path")
Signed-off-by: Jozef Hopko <jozef.hopko@altana.com>
Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
Acked-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://patch.msgid.link/20240701-wilc_fix_ies_data-v1-1-7486cbacf98a@bootlin.com