parisc: Fix set_fixmap() on PA1.x CPUs

Fix a kernel crash which happens on PA1.x CPUs while initializing the
FTRACE/KPROBE breakpoints.  The PTE table entries for the fixmap area
were not created correctly.
Signed-off-by: Helge Deller <deller@gmx.de>
Fixes: ccfbc68d ("parisc: add set_fixmap()/clear_fixmap()")
Cc: stable@vger.kernel.org # v5.2+

arch/parisc/mm/fixmap.c

@@ -20,12 +20,9 @@ void notrace set_fixmap(enum fixed_addresses idx, phys_addr_t phys)
 	pte_t *pte;
 
 	if (pmd_none(*pmd))
-		pmd = pmd_alloc(NULL, pud, vaddr);
-
-	pte = pte_offset_kernel(pmd, vaddr);
-	if (pte_none(*pte))
 		pte = pte_alloc_kernel(pmd, vaddr);
 
+	pte = pte_offset_kernel(pmd, vaddr);
 	set_pte_at(&init_mm, vaddr, pte, __mk_pte(phys, PAGE_KERNEL_RWX));
 	flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE);
 }