x86/hyper-v: Fix definition of HV_MAX_FLUSH_REP_COUNT

x86/hyper-v: Fix definition of HV_MAX_FLUSH_REP_COUNT

The max flush rep count of HvFlushGuestPhysicalAddressList hypercall is
equal with how many entries of union hv_gpa_page_range can be populated
into the input parameter page.

The code lacks parenthesis around PAGE_SIZE - 2 * sizeof(u64) which results
in bogus computations. Add them.

Fixes: cc4edae4b924 ("x86/hyper-v: Add HvFlushGuestAddressList hypercall support")
Signed-off-by: Lan Tianyu <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
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Link: https://lkml.kernel.org/r/[email protected]