lib: Don't return any invalid error from SBI ecall

We should only return valid error codes from SBI ecalls as
defined by the RISC-V SBI spec.

To achieve this:
1. We use SBI_Exxxx defines for OpenSBI internal errors with
   error values starting from -1000
2. We use SBI_ERR_xxxx defines for errors defined by SBI spec
3. We map some of the SBI_Exxxx defines to SBI_ERR_xxxx defines
   which are semantically same
4. We throw a error print and force return error code to
   SBI_ERR_FAILED in sbi_ecall_handler() if we see an invalid
   error code being returned to S-mode

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

lib/sbi/sbi_hart.c

@@ -200,7 +200,7 @@ int sbi_hart_pmp_check_addr(struct sbi_scratch *scratch, unsigned long addr,
 			continue;
 		if (tempaddr <= addr && addr <= tempaddr + size)
 			if (!(prot & attr))
-				return SBI_INVALID_ADDR;
+				return SBI_EINVALID_ADDR;
 	}
 
 	return SBI_OK;