According to C99 standard, -1 integer constant with 'U/UL'
suffix has no type.
To explicit the integer constant:
Update -1U or -1UL as ~0U or ~0UL, or invalid number according
to usage case.
V1-->V2:
Update parameter name and type of send_startup_ipi since
the second parameter is used as pcpu_id;
Update related comments for code clearity.
V2-->V3:
Update comments of struct acrn_irqline;
rename cpu_startup_dest as dest_pcpu_id in the second
parameter of send_startup_ipi.
Tracked-on: ccm0001001-247033
Signed-off-by: Xiangyang Wu <xiangyang.wu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>