bus: mhi: Fix pm_state conversion to string

bus: mhi: Fix pm_state conversion to string

On big endian architectures the mhi debugfs files which report pm state
give "Invalid State" for all states.  This is caused by using
find_last_bit which takes an unsigned long* while the state is passed in
as an enum mhi_pm_state which will be of int size.

Fix by using __fls to pass the value of state instead of find_last_bit.

Also the current API expects "mhi_pm_state" enumerator as the function
argument but the function only works with bitmasks. So as Alex suggested,
let's change the argument to u32 to avoid confusion.

Fixes: a6e2e3522f29 ("bus: mhi: core: Add support for PM state transitions")
Cc: stable@vger.kernel.org
[mani: changed the function argument to u32]
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Hemant Kumar <hemantk@codeaurora.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Paul Davey <paul.davey@alliedtelesis.co.nz>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20220301160308.107452-3-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>