shell: Fix log message queue size for all backends

188d2dfcca7 introduced a change where log message queue again
become configurable through Kconfig instead of being fixed in
the code. However, it updated only the configuration of an UART
backend. This commit updates other backends as well. Including
dummy backend which has fixed in the code value.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
diff --git a/subsys/shell/backends/Kconfig.backends b/subsys/shell/backends/Kconfig.backends
index 2b2e91e..545a53d 100644
--- a/subsys/shell/backends/Kconfig.backends
+++ b/subsys/shell/backends/Kconfig.backends
@@ -147,7 +147,7 @@
 default-timeout = 100
 source "subsys/shell/Kconfig.template.shell_log_queue_timeout"
 
-default-size = 10
+default-size = 512
 source "subsys/shell/Kconfig.template.shell_log_queue_size"
 
 choice
@@ -243,7 +243,7 @@
 default-timeout = 100
 source "subsys/shell/Kconfig.template.shell_log_queue_timeout"
 
-default-size = 10
+default-size = 512
 source "subsys/shell/Kconfig.template.shell_log_queue_size"
 
 choice
@@ -339,7 +339,7 @@
 default-timeout = 100
 source "subsys/shell/Kconfig.template.shell_log_queue_timeout"
 
-default-size = 10
+default-size = 512
 source "subsys/shell/Kconfig.template.shell_log_queue_size"
 
 choice
diff --git a/subsys/shell/backends/shell_dummy.c b/subsys/shell/backends/shell_dummy.c
index dfc30a6..61cb772 100644
--- a/subsys/shell/backends/shell_dummy.c
+++ b/subsys/shell/backends/shell_dummy.c
@@ -10,7 +10,7 @@
 #include <zephyr/init.h>
 
 SHELL_DUMMY_DEFINE(shell_transport_dummy);
-SHELL_DEFINE(shell_dummy, CONFIG_SHELL_PROMPT_DUMMY, &shell_transport_dummy, 1,
+SHELL_DEFINE(shell_dummy, CONFIG_SHELL_PROMPT_DUMMY, &shell_transport_dummy, 256,
 	     0, SHELL_FLAG_OLF_CRLF);
 
 static int init(const struct shell_transport *transport,