Rename STM32F722 gcc linker script

Author: bakatrouble

targets/TARGET_STM/TARGET_STM32F7/TARGET_STM32F722xE/CMakeLists.txt

@@ -5,7 +5,7 @@ add_subdirectory(TARGET_NUCLEO_F722ZE EXCLUDE_FROM_ALL)
 
 if(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
     set(STARTUP_FILE TOOLCHAIN_GCC_ARM/startup_stm32f722xx.S)
-    set(LINKER_FILE TOOLCHAIN_GCC_ARM/STM32F722xE.ld)
+    set(LINKER_FILE TOOLCHAIN_GCC_ARM/stm32f722xe.ld)
 elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
     set(STARTUP_FILE TOOLCHAIN_ARM/startup_stm32f722xx.S)
     set(LINKER_FILE TOOLCHAIN_ARM/stm32f722xe.sct)