dt-bindings: can: st,stm32-bxcan: fix st,gcan property type

dt-bindings: can: st,stm32-bxcan: fix st,gcan property type

The SRAM memory shared pointed to by the st,gcan property is unique, so
we don't need an array of phandles.

Fixes: e43250c0ac81 ("dt-bindings: net: can: add STM32 bxcan DT bindings")
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20241228150043.3926696-1-dario.binacchi@amarulasolutions.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>