ACPICA: Fix parameter validation for acpi_read/write
Now return AE_BAD_PARAMETER if the input register pointer is
null, and AE_BAD_ADDRESS if the register has an address of zero.
Previously, these cases simply returned AE_OK. For optional
registers such as PM1B status/enable/control, the caller should
check for a valid register address before calling. ACPICA BZ 748.