Fix typo in eTSEC Ethernet controller

IRQ are lowered when ievent bit is cleared, so irq_pulse makes no sense
here...

Signed-off-by: Fabien Chouteau <chouteau@adacore.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
spapr_nvram: Correct max nvram size

Currently it is UINT16_MAX*16 = 65536*16 = 1048560 which is not
a round number and therefore a bit confusing.

This defines MAX_NVRAM_SIZE precisely as 1MB.

Suggested-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>