lsmem: add doc for dynamic (de)configuration and memmap-on-memory support

lsmem: add doc for dynamic (de)configuration and memmap-on-memory support

lsmem --output-all now displays two new columns:

CONFIGURED : yes/no indicating if a memory block has been explicitly
configured.

MEMMAP-ON-MEMORY : yes/no indicating whether the block uses
memmap-on-memory.

lsmem -o RANGE,SIZE,STATE,BLOCK,CONFIGURED,MEMMAP-ON-MEMORY
RANGE                   SIZE   STATE   BLOCK CONFIGURED MEMMAP-ON-MEMORY
0x00000000-0x7fffffff   2G     online  0-15  yes        no
0x80000000-0xffffffff   2G     offline 16-31 no         yes

Memory block size:                128M
Total online memory:                2G
Total offline memory:               2G
Memmap on memory parameter:        yes

Add documentation for new fields.

Reviewed-by: Maria Eisenhaendler <maria1@de.ibm.com>
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>