usb: xhci-mtk: check return value in suspend/resume hooks

Return error number if encounter errors during suspend and resume.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1618031406-15347-1-git-send-email-chunfeng.yun@mediatek.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>