lrdpv2: irqparse: Fix issue while parsing irq state on 64 bit target

'irq' in 'irq_data' and 'irq_count' in 'irq_desc' are of unsigned
int (32 bit) type. Using ramdump's read_word returns 64 bit data on
64 bit target.

Fix parser to use read_int function while reading irq number.

Change-Id: I5382ea408066c2b123044a4f7612fd683da07256