kexec/ppc64: add support to parse ibm, dynamic-memory-v2 property

Add support to parse the new 'ibm,dynamic-memory-v2' property in the
'ibm,dynamic-reconfiguration-memory' node. This replaces the old
'ibm,dynamic-memory' property and is enabled in the kernel with a
patch series that starts with commit 0c38ed6f6f0b ("powerpc/pseries:
Enable support of ibm,dynamic-memory-v2"). All LMBs that share the same
flags and are adjacent are grouped together in the newer version of the
property making it compact to represent larger memory configurations.

Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Mahesh Jagannath Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Simon Horman <horms@verge.net.au>