watchdog: LENOVO_SE10_WDT should depend on X86 && DMI

The Lenovo SE10 watchdog is only present on Lenovo ThinkEdge SE10
platforms, which are based on Intel Atom SoCs, and its driver relies on
DMI tables.  Hence add dependencies on X86 && DMI, to prevent asking the
user about this driver when configuring a kernel without Intel Atom or
DMI support.

While at it, fix the odd indentation (spaces instead of TABs).

Fixes: 1f6602c8 ("watchdog: lenovo_se10_wdt: Watchdog driver for Lenovo SE10 platform")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/58005595a05ef803b454b78d3ae9b8ee0675bd5d.1715076440.git.geert+renesas@glider.be


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>