Change alignment in linker script, to remove build warning with I2S lib

.../arduino_zero/linker_scripts/gcc/flash_with_bootloader.ld

...duino_zero/linker_scripts/gcc/flash_without_bootloader.ld

variants/mkr1000/linker_scripts/gcc/flash_with_bootloader.ld

...ts/mkr1000/linker_scripts/gcc/flash_without_bootloader.ld

variants/mkrzero/linker_scripts/gcc/flash_with_bootloader.ld

...ts/mkrzero/linker_scripts/gcc/flash_without_bootloader.ld