powerpc-opal: Fix a typo in a comment line of two file headers

Fix a word in these descriptions.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/powernv/opal-hmi.c

 /*
- * OPAL hypervisor Maintenance interrupt handling support in PowreNV.
+ * OPAL hypervisor Maintenance interrupt handling support in PowerNV.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by

arch/powerpc/platforms/powernv/opal-memory-errors.c

 /*
- * OPAL asynchronus Memory error handling support in PowreNV.
+ * OPAL asynchronus Memory error handling support in PowerNV.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by