Add a new function to convert bInterval into the time expressed in 1us unit. Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/25c8a09b055f716c1e5bf11fea72c3418f844482.1615170625.git.chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> (cherry picked from commit 1b121617a69e8e4f2a7b6005ee1c0b4bcb8451fc https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-next) Signed-off-by: Greg Kroah-Hartman <gregkh@google.com> Change-Id: I4aaf4ee2bdeed01414df3d1272e6e5127722efb2