bsps/powerpc: Use ALIGN_WITH_INPUT

This requires at least Binutils 2.24.
bsps/arm: Use ALIGN_WITH_INPUT

This requires at least Binutils 2.24.
bsps: Simplify FreeBSD linker sets
bsps/m68k: Add and use linkcmds.base
bsp/genmcf548x: Add interrupt extension support
bsp/genmcf548x: Add initial values for INTC_ICRn

According to the manual the application must use unique and
non-overlapping level and priority definitions for enabled interrupts.
bsp/genmcf548x: Use bsp_interrupt_vector_enable()
bsp/genmcf548x: Fix network FIFO error handling

Use a buffer handling similar to the MPC5200B FEC driver to cope with
FIFO errors.
bsp/genmcf548x: Increase network TX FIFO watermark

This prevents frequent transmit FIFO errors.
arm: Fix set by but not used warning