xen/arm: guest_walk: LPAE specific bits should be enclosed within "ifndef CONFIG_PHYS_ADDR_T_32"

As the previous patch introduces CONFIG_PHYS_ADDR_T_32 to support 32 bit
physical addresses, the code specific to "Large Physical Address Extension"
(ie LPAE) should be enclosed within "ifndef CONFIG_PHYS_ADDR_T_32".

Refer xen/arch/arm/include/asm/short-desc.h, "short_desc_l1_supersec_t"
unsigned int extbase1:4;    /* Extended base address, PA[35:32] */
unsigned int extbase2:4;    /* Extended base address, PA[39:36] */

Thus, extbase1 and extbase2 are not valid when 32 bit physical addresses
are supported.

Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>

xen/arch/arm/guest_walk.c

@@ -154,8 +154,10 @@ static bool guest_walk_sd(const struct vcpu *v,
             mask = (1ULL << L1DESC_SUPERSECTION_SHIFT) - 1;
             *ipa = gva & mask;
             *ipa |= (paddr_t)(pte.supersec.base) << L1DESC_SUPERSECTION_SHIFT;
+#ifndef CONFIG_PHYS_ADDR_T_32
             *ipa |= (paddr_t)(pte.supersec.extbase1) << L1DESC_SUPERSECTION_EXT_BASE1_SHIFT;
             *ipa |= (paddr_t)(pte.supersec.extbase2) << L1DESC_SUPERSECTION_EXT_BASE2_SHIFT;
+#endif /* CONFIG_PHYS_ADDR_T_32 */
         }
 
         /* Set permissions so that the caller can check the flags by herself. */