cpu, sam3: adapt to sam_common

cpu/sam3/Makefile

cpu/sam3/Makefile.include

cpu/sam3/doc.txt

cpu/sam3/include/cpu_conf.h

cpu/sam3/include/periph_cpu.h

cpu/sam3/include/vendor/sam3x8e.h

cpu/sam3/include/vendor/sam3x8e/component/component_adc.h

cpu/sam3/include/vendor/sam3x8e/component/component_can.h

cpu/sam3/include/vendor/sam3x8e/component/component_chipid.h

cpu/sam3/include/vendor/sam3x8e/component/component_dacc.h

cpu/sam3/include/vendor/sam3x8e/component/component_dmac.h

cpu/sam3/include/vendor/sam3x8e/component/component_efc.h

cpu/sam3/include/vendor/sam3x8e/component/component_emac.h

cpu/sam3/include/vendor/sam3x8e/component/component_gpbr.h

cpu/sam3/include/vendor/sam3x8e/component/component_hsmci.h

cpu/sam3/include/vendor/sam3x8e/component/component_matrix.h

cpu/sam3/include/vendor/sam3x8e/component/component_pdc.h

cpu/sam3/include/vendor/sam3x8e/component/component_pio.h

cpu/sam3/include/vendor/sam3x8e/component/component_pmc.h

cpu/sam3/include/vendor/sam3x8e/component/component_pwm.h