kexec-tools: ppc64: remove rma_top limit
    
    Resolves: bz2145087
    Conflict: None
    
    commit 6b6187f546f0ddad8ea84d22c3f7ad72133dcfe3
    Author: Sourabh Jain <sourabhjain@linux.ibm.com>
    Date:   Thu Sep 15 14:12:40 2022 +0530
    
        ppc64: remove rma_top limit
    
        Restricting kexec tool to allocate hole for kexec segments below 768MB
        may not be relavent now since first memory block size can be 1024MB and
        more.
    
        Removing rma_top restriction will give more space to find holes for
        kexec segments and existing in-place checks make sure that kexec segment
        allocation doesn't cross the first memory block because every kexec segment
        has to be within first memory block for kdump kernel to boot properly.
    
        Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
        Acked-by: Hari Bathini <hbathini@linux.ibm.com>
        Signed-off-by: Simon Horman <horms@kernel.org>
    
    Signed-off-by: Coiby Xu <coxu@redhat.com>