rtc: x1205: Fix Xicor X1205 vendor prefix

rtc: x1205: Fix Xicor X1205 vendor prefix

The vendor for the X1205 RTC is not Xircom, but Xicor which was acquired
by Intersil. Since the I2C subsystem drops the vendor prefix for driver
matching, the vendor prefix hasn't mattered.

Fixes: 6875404fdb44 ("rtc: x1205: Add DT probing support")
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250821215703.869628-2-robh@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>