remove unused pmap_vp_remove() function
removed from arm64 pmap in 2022 (rev 1.87)

Index: sys/arch/riscv64/riscv64/pmap.c
===================================================================
RCS file: /cvs/src/sys/arch/riscv64/riscv64/pmap.c,v
diff -u -p -r1.40 pmap.c
--- sys/arch/riscv64/riscv64/pmap.c	6 Apr 2024 18:33:54 -0000	1.40
+++ sys/arch/riscv64/riscv64/pmap.c	29 Apr 2024 01:25:54 -0000
@@ -344,36 +344,6 @@ pmap_vp_lookup(pmap_t pm, vaddr_t va, pt
 }
 
 /*
- * Remove, and return, pted at specified address, NULL if not present
- */
-struct pte_desc *
-pmap_vp_remove(pmap_t pm, vaddr_t va)
-{
-	struct pmapvp1 *vp1;
-	struct pmapvp2 *vp2;
-	struct pmapvp3 *vp3;
-	struct pte_desc *pted;
-
-	vp1 = pm->pm_vp.l1;
-
-	vp2 = vp1->vp[VP_IDX1(va)];
-	if (vp2 == NULL) {
-		return NULL;
-	}
-
-	vp3 = vp2->vp[VP_IDX2(va)];
-	if (vp3 == NULL) {
-		return NULL;
-	}
-
-	pted = vp3->vp[VP_IDX3(va)];
-	vp3->vp[VP_IDX3(va)] = NULL;
-
-	return pted;
-}
-
-
-/*
  * Create a V -> P mapping for the given pmap and virtual address
  * with reference to the pte descriptor that is used to map the page.
  * This code should track allocations of vp table allocations