🔨 Consolidate BTT linker scripts

Originally from #22022

buildroot/share/PlatformIO/ldscripts/STM32F103RE_SKR_E3_DIP.ld

-MEMORY
-{
-  ram (rwx) : ORIGIN = 0x20000000, LENGTH = 48K - 40
-  rom (rx)  : ORIGIN = 0x08007000, LENGTH = 512K - 28K - 4K
-}
-
-/* Provide memory region aliases for common.inc */
-REGION_ALIAS("REGION_TEXT", rom);
-REGION_ALIAS("REGION_DATA", ram);
-REGION_ALIAS("REGION_BSS", ram);
-REGION_ALIAS("REGION_RODATA", rom);
-
-/* Let common.inc handle the real work. */
-INCLUDE common.inc

ini/stm32f1-maple.ini

 upload_protocol      = jlink
 
 #
+# BigTree SKR Mini E3 DIP / SKR CR6 (STM32F103RET6 ARM Cortex-M3)
+#
 #   STM32F103RE_btt ............. RET6
 #   STM32F103RE_btt_USB ......... RET6 (USB mass storage)
 #
 platform          = ${common_stm32f1.platform}
 extends           = env:STM32F103RE_maple
 board_build.address  = 0x08007000
-board_build.ldscript = STM32F103RE_SKR_E3_DIP.ld
+board_build.ldscript = STM32F103RE_SKR_MINI_512K.ld
 extra_scripts     = ${common_stm32f1.extra_scripts}
   buildroot/share/PlatformIO/scripts/custom_board.py
 build_flags       = ${common_stm32f1.build_flags} -DDEBUG_LEVEL=0 -DSS_TIMER=4