x86/platform/olpc: Do not call of_platform_bus_probe()

The DT core will probe the DT by default now, so the OLPC platform code
calling of_platform_bus_probe() is not necessary. The algorithm for what
nodes are probed is a little different in how compatible is handled, but
since OLPC uses compatible strings for matching it is not affected by
this difference.

Also, only the battery node located at the root level gets a device
created as the dcon is a PCI device and the RTC device is created in
olpc-xo1-rtc.c.

Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: Lubomir Rintel <lkundrak@v3.sk>
Cc: Thomas Gleixner <tglx@linutronix.de>
CC: devicetree@vger.kernel.org
CC: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/20181116201820.10065-1-robh@kernel.org