powerpc/powernv: Only delay opal_rtc_read() retry when necessary

[Michael Ellerman]

On Fri, 2015-18-12 at 10:46:04 UTC, Michael Neuling wrote:
> Only delay opal_rtc_read() when busy and are going to retry.
> 
> This has the advantage of possibly saving a massive 10ms off booting!
> 
> Kudos to Stewart for noticing.
> 
> Signed-off-by: Michael Neuling <mikey at neuling.org>
> Reviewed-by: Stewart Smith <stewart at linux.vnet.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/57a9039052aadf5833c40ab494

cheers