fix(stm32mp1-fdts): remove mmc1 alias if not needed

If a board declares an mmc1 alias in its DT and is compiled without flags
STM32MP_EMMC or STM32MP_SDMMC, the DT will fail to build.
Add /delete-property/ mmc1; to correct this.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: I1938ff99dc3d883f9174ee886f9ffa195ec60373
diff --git a/fdts/stm32mp15-bl2.dtsi b/fdts/stm32mp15-bl2.dtsi
index 074414b..d00e35b 100644
--- a/fdts/stm32mp15-bl2.dtsi
+++ b/fdts/stm32mp15-bl2.dtsi
@@ -1,12 +1,13 @@
 // SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
 /*
- * Copyright (C) STMicroelectronics 2020-2021 - All Rights Reserved
+ * Copyright (C) STMicroelectronics 2020-2022 - All Rights Reserved
  */
 
 / {
 #if !STM32MP_EMMC && !STM32MP_SDMMC
 	aliases {
 		/delete-property/ mmc0;
+		/delete-property/ mmc1;
 	};
 #endif