tests: set shmmni to 32k

Linux kernel since 6730e6580177d13f4612767873cb5a533ad63c61 checks for
limits and kernel ipc/utils.h defines

 #define IPCMNI_SHIFT         15
 #define IPCMNI               (1 << IPCMNI_SHIFT)

it means 32768 (aka shortint max). Let's use it in our tests too to
avoid "Invalid argument" when write to /proc/sys/kernel/shmmni.

Signed-off-by: Karel Zak <kzak@redhat.com>

tests/ts/ipcs/functions.sh

@@ -55,7 +55,7 @@ IPCS_CMD=(
 #  ... it's a problem for admins who want to use 75557863725TB of RAM for shm)
 #
 IPCS_LIMITS=(
-	$($TS_HELPER_SYSINFO INT_MAX)
+	32768
 	$($TS_HELPER_SYSINFO ULONG_MAX32)
 	$($TS_HELPER_SYSINFO ULONG_MAX32)
 )