SI13: Set DRX_TIMER_MAX value actually transmitted

The set of values in seconds which can be expressed in the 3-bit field
DRX_TIMER_MAX (0s, 1s, 2s, 4s,...64s) don't include the "3s" that where
being specified. Instead, libosmocore's encode_drx_timer() was
taking both upper boundary "4s" and encoding it "0b011".
Hence, better write the value actually being transmitted to MS, to avoid
users/readers confusion.

More related info can be found on TS 44.060 Table 12.24.2 and TS 45.002
6.5.6.

Related: OS#6097
Change-Id: Ibf01a50b258e197ba5e3173492513349ddffdb38
---
M src/osmo-bsc/system_information.c
1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/osmo-bsc/system_information.c b/src/osmo-bsc/system_information.c
index 35fce68..9ed77f9 100644
--- a/src/osmo-bsc/system_information.c
+++ b/src/osmo-bsc/system_information.c
@@ -1244,7 +1244,7 @@
 			.nmo		= GPRS_NMO_II,
 			.t3168		= 2000,
 			.t3192		= 1500,
-			.drx_timer_max	= 3,
+			.drx_timer_max	= 4,
 			.bs_cv_max	= 15,
 			.ctrl_ack_type_use_block = bts->gprs.ctrl_ack_type_use_block,
 			.ext_info_present = true,

