soc: qcom: geni-se: Add M_TX_FIFO_NOT_EMPTY bit definition

According to the docs I have, bit 21 of the status register is
asserted when the FIFO is _not_ empty. Add the definition.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20240112150307.1.I7dc0993c1e758a1efedd651e7e1670deb1b430fb@changeidSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/soc/qcom/geni-se.h

@@ -178,6 +178,7 @@ struct geni_se {
 #define M_GP_IRQ_3_EN			BIT(12)
 #define M_GP_IRQ_4_EN			BIT(13)
 #define M_GP_IRQ_5_EN			BIT(14)
+#define M_TX_FIFO_NOT_EMPTY_EN		BIT(21)
 #define M_IO_DATA_DEASSERT_EN		BIT(22)
 #define M_IO_DATA_ASSERT_EN		BIT(23)
 #define M_RX_FIFO_RD_ERR_EN		BIT(24)