Update board_f_cpu to board_build.f_cpu

platformio.ini

@@ -16,9 +16,9 @@
 #
 
 [platformio]
-src_dir = Marlin
-build_dir = .pioenvs
-lib_dir = .piolib
+src_dir     = Marlin
+build_dir   = .pioenvs
+lib_dir     = .piolib
 libdeps_dir = .piolibdeps
 env_default = megaatmega2560
 
@@ -50,25 +50,25 @@ lib_deps =
 # ATmega2560
 #
 [env:megaatmega2560]
-platform      = atmelavr
-framework     = arduino
-board         = megaatmega2560
-build_flags   = ${common.build_flags}
-board_f_cpu   = 16000000L
-lib_deps      = ${common.lib_deps}
-monitor_speed = 250000
+platform          = atmelavr
+framework         = arduino
+board             = megaatmega2560
+build_flags       = ${common.build_flags}
+board_build.f_cpu = 16000000L
+lib_deps          = ${common.lib_deps}
+monitor_speed     = 250000
 
 #
 # ATmega1280
 #
 [env:megaatmega1280]
-platform      = atmelavr
-framework     = arduino
-board         = megaatmega1280
-build_flags   = ${common.build_flags}
-board_f_cpu   = 16000000L
-lib_deps      = ${common.lib_deps}
-monitor_speed = 250000
+platform          = atmelavr
+framework         = arduino
+board             = megaatmega1280
+build_flags       = ${common.build_flags}
+board_build.f_cpu = 16000000L
+lib_deps          = ${common.lib_deps}
+monitor_speed     = 250000
 
 #
 # AT90USB1286 boards using CDC bootloader
@@ -129,13 +129,13 @@ monitor_speed = 250000
 # RAMBo
 #
 [env:rambo]
-platform      = atmelavr
-framework     = arduino
-board         = reprap_rambo
-build_flags   = ${common.build_flags}
-board_f_cpu   = 16000000L
-lib_deps      = ${common.lib_deps}
-monitor_speed = 250000
+platform          = atmelavr
+framework         = arduino
+board             = reprap_rambo
+build_flags       = ${common.build_flags}
+board_build.f_cpu = 16000000L
+lib_deps          = ${common.lib_deps}
+monitor_speed     = 250000
 
 #
 # Sanguinololu (ATmega644p)
@@ -163,11 +163,11 @@ monitor_speed = 250000
 # Teensy++ 2.0
 #
 [env:teensy20]
-platform      = teensy
-framework     = arduino
-board         = teensy20pp
-build_flags   = ${common.build_flags}
-#board_f_cpu  = 20000000L     ; Bug in Arduino framework disallows boards running at 20Mhz
-lib_deps      = ${common.lib_deps}
-lib_ldf_mode  = deep+
-monitor_speed = 250000
+platform          = teensy
+framework         = arduino
+board             = teensy20pp
+build_flags       = ${common.build_flags}
+#board_build.f_cpu = 20000000L     ; Bug in Arduino framework disallows boards running at 20Mhz
+lib_deps          = ${common.lib_deps}
+lib_ldf_mode      = deep+
+monitor_speed     = 250000