wifi: rtw89: debug: disable inactive power save to reduce bus overhead

wifi: rtw89: debug: disable inactive power save to reduce bus overhead

This helps avoid excessive bus traffic and I/O overhead on
slower HCIs (e.g., USB, SDIO) caused by frequent power state
transitions.

Add RTW89_DM_INACTIVE_PS to the disabled_dm bitmap via debugfs and
check it in the rtw89_enter_ips path. When set, the driver skips
entering inactive power save and returns immediately.

Signed-off-by: Johnson Tsai <wenjie.tsai@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20260420034051.17666-5-pkshih@realtek.com