Limit tables to 50000 samples to avoid loose pulses

Current setup doesn't allow to work on 14Hz, and write tables greater
than 50000 samples without loose some pulses.
This is a work around until the root cause of this is identified

iocsh/sis8300llrf.iocsh

@@ -4,8 +4,8 @@
 #######################
 epicsEnvSet("LLRF_NOPULSETYPES" "$(SIS8300LLRF_NOPULSETYPES=1)")
 
-epicsEnvSet("SP_SMNM_MAX"              "0xFFFFFF")
-epicsEnvSet("FF_SMNM_MAX"              "0xFFFFFF")
+epicsEnvSet("SP_SMNM_MAX"              "0xC350")
+epicsEnvSet("FF_SMNM_MAX"              "0xC350")
 epicsEnvSet("PIERR_SMNM_MAX"           "0x10000")
 epicsEnvSet("AI_SMNM_MAX"              "0x200000")       
 epicsEnvSet("CAL_SMNM_MAX"              "1000")