drmgr: Fix LMB lookup by index
drmgr: Fix LMB lookup by index

From: Bharata B Rao <37852461ec08f94420c663824224090aed552843@linux.vnet.ibm.com>

If drc_index is used with -s option and the drc_index specified
doesn't correspond to the first available unused LMB, get_available_lmb()
ends up returning first available LMB that doesn't match the requested
drc_index.

Fix this by explicitly checking for drc_index when drc_index is specified
with -s option.

Signed-off-by: Bharata B Rao <37852461ec08f94420c663824224090aed552843@linux.vnet.ibm.com>

kamalesh-babulal/powerpc-utils,kamalesh-babulal/powerpc-utils,mdroth/powerpc-utils,shenki/powerpc-utils,kamalesh-babulal/powerpc-utils,shenki/powerpc-utils,shenki/powerpc-utils,mdroth/powerpc-utils,mdroth/powerpc-utils