docs/hwmon: Fix broken links warnings in lm90.rst

docs/hwmon: Fix broken links warnings in lm90.rst

This patch fixes warnings in Documentation/hwmon/lm90.rst reported when
running 'make linkcheckdocs'.

On 2011-09-23 National Semiconductors became part of Texas Instruments
and national.com is no longer accessible. The datasheet resources for
the chips are now available at Texas Instruments website and have been
updated for lm90.

In 2021, Maxim Integrated was acquired by Analog Devices and maxim-ic.com
redirects to analog.com. The chip datasheets are now available at
Analog Devices and have been updated accordingly.

Some additional broken or unavailable links have been replaced with
equivalents hosted by DigiKey.

Signed-off-by: Ankan Biswas <spyjetfayed@gmail.com>
Link: https://lore.kernel.org/r/20251016103049.2573-1-spyjetfayed@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>