esp32/esp32_common.cmake: Remove obsolete definition.

This commit removes a definition used back when ESP-IDF v4 was supported
by MicroPython.  Those times are now long gone, and so is the need for
that particular definition to be set in the first place.

Signed-off-by: Alessandro Gatti <[email protected]>

Author: agatti

ports/esp32/esp32_common.cmake

@@ -247,7 +247,6 @@ target_compile_definitions(${MICROPY_TARGET} PUBLIC
     ${MICROPY_DEF_CORE}
     ${MICROPY_DEF_BOARD}
     ${MICROPY_DEF_TINYUSB}
-    MICROPY_ESP_IDF_4=1
     MICROPY_VFS_FAT=1
     MICROPY_VFS_LFS2=1
     FFCONF_H=\"${MICROPY_OOFATFS_DIR}/ffconf.h\"