removed unused .a and fixed frequency

Author: ladyada

boards.txt

@@ -286,7 +286,7 @@ adafruit_metro_m4.upload.use_1200bps_touch=true
 adafruit_metro_m4.upload.wait_for_upload_port=true
 adafruit_metro_m4.upload.native_usb=true
 adafruit_metro_m4.build.mcu=cortex-m4
-adafruit_metro_m4.build.f_cpu=48000000L
+adafruit_metro_m4.build.f_cpu=120000000L
 adafruit_metro_m4.build.usb_product="Adafruit Metro M4"
 adafruit_metro_m4.build.usb_manufacturer="Adafruit LLC"
 adafruit_metro_m4.build.board=METRO_M4
@@ -317,7 +317,7 @@ adafruit_metro_m4.compiler.arm.cmsis.ldflags="-L{build.variant.path}" -larm_cort
 #adafruit_feather_m4.upload.wait_for_upload_port=true
 #adafruit_feather_m4.upload.native_usb=true
 #adafruit_feather_m4.build.mcu=cortex-m4
-#adafruit_feather_m4.build.f_cpu=48000000L
+#adafruit_feather_m4.build.f_cpu=120000000L
 #adafruit_feather_m4.build.usb_product="Adafruit Feather M4"
 #adafruit_feather_m4.build.usb_manufacturer="Adafruit LLC"
 #adafruit_feather_m4.build.board=FEATHER_M4