x86/pvh: change epte_get_entry_emt() for pvh mem types

x86/pvh: change epte_get_entry_emt() for pvh mem types

For pvh guests, epte_get_entry_emt() is incorrectly returning WB for
all mem types because of the following check:
    if ( !v->domain->arch.hvm_domain.params[HVM_PARAM_IDENT_PT] )
Skip the check for pvh guests.

Also note, MTRR ranges are not maintained for pvh, and a solution is
being contrived using PAT.

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Reviewed-off-by: Jan Beulich <jbeulich@suse.com>