wifi: wilc1000: Re-enable RTC clock on resume

The wilc_sdio_suspend() does clk_disable_unprepare() on rtc_clk clock,
make sure wilc_sdio_resume() does matching clk_prepare_enable(), else
any suspend/resume cycle leads to clock disable/enable imbalance. Fix
the imbalance.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Alexis Lothoré <alexis.lothore@bootlin.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://patch.msgid.link/20240821183717.163235-1-marex@denx.de