x86/platform/intel-mid: Revert "Make 'bt_sfi_data' const"

So one of the constification patches unearthed a type casting fragility
of the underlying code:

  276c870 ("x86/platform/intel-mid: Make 'bt_sfi_data' const")

converted the struct to be const while it is also used as a temporary
container for important data that is used to fill 'parent' and 'name'
fields in struct platform_device_info.

The compiler doesn't notice this due to an explicit type cast that loses
the const - which fragility will be fixed separately.

This type cast turned a seemingly trivial const propagation patch into a
hard to debug data corruptor and crasher bug.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Bhumika Goyal <bhumirks@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: julia.lawall@lip6.fr
Cc: platform-driver-x86@vger.kernel.org
Link: http://lkml.kernel.org/r/20171228122523.21802-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/platform/intel-mid/device_libs/platform_bt.c

@@ -60,7 +60,7 @@ static int __init tng_bt_sfi_setup(struct bt_sfi_data *ddata)
 	return 0;
 }
 
-static const struct bt_sfi_data tng_bt_sfi_data __initdata = {
+static struct bt_sfi_data tng_bt_sfi_data __initdata = {
 	.setup	= tng_bt_sfi_setup,
 };