[PATCH] xen/riscv: fix build issue for bullseye-riscv64 container

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Address compilation error on bullseye-riscv64 container:
   undefined reference to `guest_physmap_remove_page`

Since there is no current implementation of `guest_physmap_remove_page()`,
a stub function has been added.

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
Reported-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/riscv/stubs.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/xen/arch/riscv/stubs.c b/xen/arch/riscv/stubs.c
index b67d99729f..3285d18899 100644
--- a/xen/arch/riscv/stubs.c
+++ b/xen/arch/riscv/stubs.c
@@ -381,6 +381,12 @@ int arch_get_paging_mempool_size(struct domain *d, 
uint64_t *size)
     BUG_ON("unimplemented");
 }
 
+int guest_physmap_remove_page(struct domain *d, gfn_t gfn, mfn_t mfn,
+                              unsigned int page_order)
+{
+    BUG_ON("unimplemented");
+}
+
 /* delay.c */
 
 void udelay(unsigned long usecs)
-- 
2.45.2