ppc/xive2: Support crowd-matching when looking for target

ppc/xive2: Support crowd-matching when looking for target

XIVE crowd sizes are encoded into a 2-bit field as follows:
  0: 0b00
  2: 0b01
  4: 0b10
 16: 0b11

A crowd size of 8 is not supported.

If an END is defined with the 'crowd' bit set, then a target can be
running on different blocks. It means that some bits from the block
VP are masked when looking for a match. It is similar to groups, but
on the block instead of the VP index.

Most of the changes are due to passing the extra argument 'crowd' all
the way to the function checking for matches.

Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Glenn Miles <milesg@linux.vnet.ibm.com>
Signed-off-by: Michael Kowal <kowal@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>