watchdog: remove driver for integrated WDT of ZFx86 486-based SoC

watchdog: remove driver for integrated WDT of ZFx86 486-based SoC

The machzwd driver supports the integrated watchdog of the ZF Micro
ZFx86 SoC, which contains a 486-compatible core [1]. Since 486
support was removed in commit 8b793a92d862 ("x86/cpu: Remove
M486/M486SX/ELAN support"), the driver is no longer useful, Remove it.

[1] https://www.zfmicro.com/zfx86.html

Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20260428014806.35400-1-enelsonmoore@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>