pm80xx: Remove bogus address masking in pm8001_ioremap()

It is unclear what the original intent of the masking was, but it is
clearly incorrect to truncate a physical address before calling
ioremap().  On systems where there are valid physical address bits above
bit-31 (arm64 for example) the result is an eventual OOPs when
initializing the driver.

Remove the bogus code to fix it.

Signed-off-by: David Daney <david.daney@cavium.com>
Acked-by: Jack Wang <jinpu.wang@profitbricks.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>