samples: cellular: modem_shell: Temp fix for Thingy91x

Setting CONFIG_UART_NRFX_UARTE_LEGACY_SHIM=n because having it enabled
makes Thingy91x jam early in the boot.

Suspecting nrfconnect/sdk-zephyr#2146

Proper fix will be analyzed and handled in NCSDK-29992.

Signed-off-by: Tommi Rantanen <[email protected]>

Author: trantanen

samples/cellular/modem_shell/boards/thingy91x_nrf9151_ns.conf

@@ -14,3 +14,6 @@ CONFIG_IMG_MANAGER=y
 CONFIG_STREAM_FLASH=y
 CONFIG_MCUBOOT_IMG_MANAGER=y
 CONFIG_IMG_ERASE_PROGRESSIVELY=y
+
+# Hopefully a temporary UART config to fix jam in the boot
+CONFIG_UART_NRFX_UARTE_LEGACY_SHIM=n