powerpc/crash: preserve user-specified memory limit

Commit 59d58189 ("crash: fix crash memory reserve exceed system memory
bug") fails crashkernel parsing if the crash size is found to be higher
than system RAM, which makes the memory_limit adjustment code ineffective
due to an early exit from reserve_crashkernel().

Regardless lets not violate the user-specified memory limit by adjusting
it.  Remove this adjustment to ensure all reservations stay within the
limit.  Commit f94f5ac0 ("powerpc/fadump: Don't update the
user-specified memory limit") did the same for fadump.

Link: https://lkml.kernel.org/r/20250131113830.925179-6-sourabhjain@linux.ibm.com


Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Cc: Baoquan he <bhe@redhat.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>