meta-ibm: Remove unnecessary setting BMC_RW_SIZE

This variable is set to 0x600000 by default in the phosphor layer - no
need to override it again in meta-ibm.

Change-Id: I1b6717dafec89bc12f700091f4b93ecce32a1b69
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
1 file changed