staging: r8188eu: clean up the code to set ips_deny_time

staging: r8188eu: clean up the code to set ips_deny_time

Clean up the code in rtw_pwr_wakeup that sets pwrpriv->ips_deny_time.

Make ips_deny_time an unsigned long, this type is used by the kernel
functions that process jiffies.

Remove the temporary variable ips_deffer_ms and use
RTW_PWR_STATE_CHK_INTERVAL directly.

There's no need to set ips_deny_time twice, it's sufficient to set it at
the end of rtw_pwr_wakeup.

Use time_before to check if ips_deny_time should be updated.

We can now remove rtw_ms_to_systime, this function is not used any more.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20220413193654.258507-7-martin@kaiser.cx
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>