Initializing the clocks in the SPL brings Rockbox in line with
how the FiiO M3K's original SPL works. It's likely other X1000
devices do this too.
There was a logic error in the previous setup: the code falsely
assumed that DDR memory would always be running from MPLL, but
it would be switched to APLL by the bootloader. Rockbox would
then try to re-init APLL, albeit with the same parameters. Maybe
this was the cause of the boot hang on some units.
Change-Id: I64064585e491bbdf1e95fe9428c91a9314f2a917
SPL is now designed so core X1000 code is in control of the boot,
under the reasonable assumption that the device boots from flash.
It should not be too hard to adapt to other X1000 ports.
The biggest functional change is that the SPL can now read/write
the flash, under the control of a host computer. The SPL relies
on the boot ROM for USB communication, so the host has to execute
the SPL multiple times following a protocol.
Change-Id: I3ffaa00e4bf191e043c9df0e2e64d15193ff42c9