🐛 Fix env:chitu_f103 (#23225)

ini/stm32f1.ini

 extends              = stm32_variant
 board                = genericSTM32F103ZE
 board_build.variant  = MARLIN_F103Zx
+board_build.offset   = 0x8800
 build_flags          = ${stm32_variant.build_flags}
-                       -DSTM32F1xx -DSTM32_XL_DENSITY
+                       -DSTM32F1xx
 build_unflags        = ${stm32_variant.build_unflags}
 extra_scripts        = ${stm32_variant.extra_scripts}
                        buildroot/share/PlatformIO/scripts/chitu_crypt.py