zipl: make BLK_PWRT unsigned int
zipl: make BLK_PWRT unsigned int

Otherwise there might be a compiler warning when using 'MIN(bl_count,
BLK_PWRT)'.

Reviewed-by: Philipp Rudo <ebc9ed60c9e1dc6a17c00cf7f6009c740d3c3928@linux.ibm.com>
Reviewed-by: Stefan Haberland <dec981e3bbb165d021029c42291faf06f59827c1@linux.ibm.com>
Signed-off-by: Marc Hartmayer <7bafc8cd4e6394916d396e4f8cde69753be8d066@linux.ibm.com>
Signed-off-by: Jan Höppner <96138615ab4af0813785fa10d283f3d37eca3b78@linux.ibm.com>

ibm-s390-tools/s390-tools,ibm-s390-tools/s390-tools,ibm-s390-tools/s390-tools,ibm-s390-tools/s390-tools