LoongArch: Print symbol info for $ra and CSR.ERA only for kernel-mode contexts

Otherwise the addresses wouldn't make sense at all.

While at it, align the "map keys" to maintain right-alignment with the
"estat:" line too; also swap the ERA and ra lines so all CSRs are shown
together.

Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>