PM: hibernate: Support to select compression algorithm

PM: hibernate: Support to select compression algorithm

Currently the default compression algorithm is selected based on
compile time options. Introduce a module parameter "hibernate.compressor"
to override this behaviour.

Different compression algorithms have different characteristics and
hibernation may benefit when it uses any of these algorithms, especially
when a secondary algorithm(LZ4) offers better decompression speeds over
a default algorithm(LZO), which in turn reduces hibernation image
restore time.

Users can override the default algorithm in two ways:

 1) Passing "hibernate.compressor" as kernel command line parameter.
    Usage:
    	LZO: hibernate.compressor=lzo
    	LZ4: hibernate.compressor=lz4

 2) Specifying the algorithm at runtime.
    Usage:
	LZO: echo lzo > /sys/module/hibernate/parameters/compressor
	LZ4: echo lz4 > /sys/module/hibernate/parameters/compressor

Currently LZO and LZ4 are the supported algorithms. LZO is the default
compression algorithm used with hibernation.

Signed-off-by: Nikhil V <quic_nprakash@quicinc.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>