platform/x86: Move Mellanox platform hotplug driver to platform/mellanox

In preparation for making the hotplug driver build for different
architectures, move mlxcpld-hotplug.c to platform/mellanox and the
header to include/linux/platform_data as mlxreg.h to reflect the new
interface changes to come.

Replace references to CPLD with REG throughout the files, consistent
with the new name.

Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
[dvhart: update copyright, rewrite commit message]
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
diff --git a/drivers/platform/Makefile b/drivers/platform/Makefile
index d3a6630..4b2ce58 100644
--- a/drivers/platform/Makefile
+++ b/drivers/platform/Makefile
@@ -4,6 +4,7 @@
 #
 
 obj-$(CONFIG_X86)		+= x86/
+obj-$(CONFIG_MELLANOX_PLATFORM)	+= mellanox/
 obj-$(CONFIG_MIPS)		+= mips/
 obj-$(CONFIG_OLPC)		+= olpc/
 obj-$(CONFIG_GOLDFISH)		+= goldfish/