Merge pull request adafruit#443 from dhalbert/3.0_spi

non-DMA SPI working; adding this now for testing; will continue with DMA

Author: dhalbert

ports/atmel-samd/Makefile

@@ -172,6 +172,7 @@ SRC_ASF := \
 hal/src/hal_i2c_m_sync.c \
 hal/src/hal_io.c \
 hal/src/hal_sleep.c \
+hal/src/hal_spi_m_sync.c \
 hal/src/hal_timer.c \
 hal/src/hal_usb_device.c \
 hpl/core/hpl_init.c \
@@ -251,6 +252,7 @@ SRC_COMMON_HAL = \
 board/__init__.c \
 busio/__init__.c \
 busio/I2C.c \
+busio/SPI.c \
 digitalio/__init__.c \
 digitalio/DigitalInOut.c \
 microcontroller/__init__.c \
@@ -266,7 +268,6 @@ SRC_COMMON_HAL = \
 audiobusio/PDMIn.c \
 audioio/__init__.c \
 audioio/AudioOut.c \
-busio/SPI.c \
 busio/UART.c \
 neopixel_write/__init__.c \
 nvm/__init__.c \