ath10k: increase AST table SKID length limit

The current SKID length configuration causes firmware
to reject peer creation for not able to allocate
AST entries for peers. This issue is observed when
least significant 3 bytes are used ramdomly to create
client MAC addresses.

AST table SKID length configuration is increased to
maximum value to fix this issue.

Signed-off-by: SenthilKumar Jegadeesan <sjegadee@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>