platform/x86: wmi: move struct wmi_device_id to mod_devicetable.h

In preparation for adding WMI support to MODULE_DEVICE_TABLE() move the
definition of struct wmi_device_id to mod_devicetable.h and inline
guid_string in the struct.

Changing guid_string to an inline char array changes the loop conditions
when looping over an array of struct wmi_device_id. Therefore update
wmi_dev_match()'s loop to check for an empty guid_string instead of a
NULL pointer.

Signed-off-by: Mattias Jacobsson <2pi@mok.nu>
[dvhart: Move UUID_STRING_LEN define to this patch]
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>

scripts/mod/file2alias.c

@@ -37,6 +37,7 @@ typedef unsigned char	__u8;
 typedef struct {
 	__u8 b[16];
 } uuid_le;
+#define	UUID_STRING_LEN		36
 
 /* Big exception to the "don't include kernel headers into userspace, which
  * even potentially has different endianness and word sizes, since