A number of devices on i.MX6 list "syscon" as second compatibility
string, among them, most importantly, is "iomuxv3" pinmux driver, which
gets probed at "postcore_initcall". Probing this driver at
"core_initcall" results in "syscon" driver usurping pinmux device and
preventing "iomuxv3" driver from loading and correctly initializing
pinmux of the system (which in turn results in a lot of sadness).

Moving this driver to be initialized at "device_initcall" time resolves
the issue.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>