xen/arm: Remove flush_xen_text_tlb_local()

xen/arm: Remove flush_xen_text_tlb_local()

The function flush_xen_text_tlb_local() has been misused and will result
to invalidate the instruction cache more than necessary.

For instance, there is no need to invalidate the instruction cache if
we are setting SCTLR_EL2.WXN.

There is effectively only one caller (i.e free_init_memory() who would
need to invalidate the instruction cache.

So rather than keeping around the function flush_xen_text_tlb_local()
replace it with call to flush_xen_tlb_local() and explicitly flush
the cache when necessary.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Andrii Anisov <andrii_anisov@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>