xen/arm: Don't pad between function with x86 nops

This was copy&paste from x86.  It causes the padding between functions to be:

  a000026dd64:   90909090        adrp    x16, 9ff2147d000 <start-0xded83000>

rather than:

  a000026dd64:   00000000        udf     #0

No functional change.

Fixes: 5da0d3123c ("arm: entry.S and head.S")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>

xen/arch/arm/xen.lds.S

@@ -47,7 +47,7 @@ SECTIONS
 
        *(.gnu.warning)
        _etext = .;             /* End of text section */
-  } :text = 0x9090
+  } :text
 
   . = ALIGN(PAGE_SIZE);
   .rodata : {