riscv: don't export va_kernel_pa_offset in vmcoreinfo for XIP kernel

The crash utility uses va_kernel_pa_offset to translate virtual addresses.
This is incorrect in the case of XIP kernel, because va_kernel_pa_offset is
not the virtual-physical address offset (yes, the name is misleading; this
variable will be removed for XIP in a following commit).

Stop exporting this variable for XIP kernel. The replacement is to be
determined, note it as a TODO for now.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/8f8760d3f9a11af4ea0acbc247e4f49ff5d317e9.1717789719.git.namcao@linutronix.deSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/kernel/vmcore_info.c

@@ -19,6 +19,13 @@ void arch_crash_save_vmcoreinfo(void)
 #endif
 #endif
 	vmcoreinfo_append_str("NUMBER(KERNEL_LINK_ADDR)=0x%lx\n", KERNEL_LINK_ADDR);
+#ifdef CONFIG_XIP_KERNEL
+	/* TODO: Communicate with crash-utility developers on the information to
+	 * export. The XIP case is more complicated, because the virtual-physical
+	 * address offset depends on whether the address is in ROM or in RAM.
+	 */
+#else
 	vmcoreinfo_append_str("NUMBER(va_kernel_pa_offset)=0x%lx\n",
 						kernel_map.va_kernel_pa_offset);
+#endif
 }