Rename sbi_save to parse_dtb to improve code readability

The sbi_ prefix would seem to indicate an SBI interface, and save is not
very specific. After applying this patch, reading head.S makes more sense.

Signed-off-by: Michael Clark <michaeljclark@mac.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

arch/riscv/kernel/setup.c

@@ -144,7 +144,7 @@ asmlinkage void __init setup_vm(void)
 #endif
 }
 
-void __init sbi_save(unsigned int hartid, void *dtb)
+void __init parse_dtb(unsigned int hartid, void *dtb)
 {
 	early_init_dt_scan(__va(dtb));
 }