riscv: don't read back satp in paging_init

init_mm.pgd (aka swapped_pgd) gets relocated like all other kernel
symbols by the elf loader, so there is no need to reload it from satp.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

arch/riscv/mm/init.c

@@ -41,8 +41,6 @@ void setup_zero_page(void)
 
 void __init paging_init(void)
 {
-	init_mm.pgd = (pgd_t *)pfn_to_virt(csr_read(sptbr));
-
 	setup_zero_page();
 	local_flush_tlb_all();
 	zone_sizes_init();