doc/kwboot.1: Update Armada 38x BootROM bug description

Replace SPI-NOR by default boot source location as bug is not SPI-NOR related.

Signed-off-by: Pali Rohár <pali@kernel.org>
diff --git a/doc/kwboot.1 b/doc/kwboot.1
index 5cda3b4..32d324f 100644
--- a/doc/kwboot.1
+++ b/doc/kwboot.1
@@ -69,7 +69,7 @@
 .IP
 
 Armada 38x BootROM has a bug which cause that BootROM's standard output
-is turned off on UART when SPI-NOR contains valid boot image. Nevertheless
+is turned off on UART when default boot source location contains valid boot image. Nevertheless
 BootROM's standard input and BootROM's terminal echo are active and working
 fine. To workaround this BootROM bug with standard output, it is possible
 to manually overwrite BootROM variables stored in SRAM which BootROM use