[nrf fromlist] tests: boards: nrf: i2c_slave: allow more instances

Allow more TWIS instances to be tested.

Upstream PR #: 91402

Signed-off-by: Michał Stasiak <[email protected]>
(cherry picked from commit bcf554e)

Author: mstasiaknordic

tests/boards/nrf/i2c/i2c_slave/src/main.c

@@ -21,8 +21,14 @@
 #define I2C_S_INSTANCE 1
 #elif CONFIG_NRFX_TWIS2
 #define I2C_S_INSTANCE 2
+#elif CONFIG_NRFX_TWIS20
+#define I2C_S_INSTANCE 20
+#elif CONFIG_NRFX_TWIS21
+#define I2C_S_INSTANCE 21
 #elif CONFIG_NRFX_TWIS22
 #define I2C_S_INSTANCE 22
+#elif CONFIG_NRFX_TWIS30
+#define I2C_S_INSTANCE 30
 #elif CONFIG_NRFX_TWIS131
 #define I2C_S_INSTANCE 131
 #else