drivers: acpi: don't use own implementation of hex_to_bin()

Remove own implementation of hex_to_bin().

Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/acpi/bus.c

@@ -401,11 +401,6 @@ static void acpi_print_osc_error(acpi_handle handle,
 	printk("\n");
 }
 
-static u8 hex_val(unsigned char c)
-{
-	return isdigit(c) ? c - '0' : toupper(c) - 'A' + 10;
-}
-
 static acpi_status acpi_str_to_uuid(char *str, u8 *uuid)
 {
 	int i;
@@ -422,8 +417,8 @@ static acpi_status acpi_str_to_uuid(char *str, u8 *uuid)
 			return AE_BAD_PARAMETER;
 	}
 	for (i = 0; i < 16; i++) {
-		uuid[i] = hex_val(str[opc_map_to_uuid[i]]) << 4;
-		uuid[i] |= hex_val(str[opc_map_to_uuid[i] + 1]);
+		uuid[i] = hex_to_bin(str[opc_map_to_uuid[i]]) << 4;
+		uuid[i] |= hex_to_bin(str[opc_map_to_uuid[i] + 1]);
 	}
 	return AE_OK;
 }