cleanup: apply remove_atoi_casts.cocci (coccinelle)

cpu/kinetis_common/dist/calc_spi_scalers/calc_spi_scalers.c

examples/dtls-echo/dtls-client.c

examples/emcute/main.c

examples/gcoap/gcoap_cli.c

examples/gnrc_networking/udp.c

examples/posix_sockets/udp.c

sys/shell/commands/sc_gnrc_6ctx.c

sys/shell/commands/sc_gnrc_rpl.c

sys/shell/commands/sc_netif.c

sys/shell/commands/sc_saul_reg.c

tests/driver_dynamixel/main.c

tests/driver_feetech/main.c

tests/driver_kw2xrf/main.c

tests/driver_pcd8544/main.c

tests/driver_sdcard_spi/main.c

tests/driver_srf02/main.c

tests/emb6/udp.c

tests/periph_uart/main.c