hw/ssi/aspeed_smc: Fix incorrect FMC_WDT2 register read on AST1030

hw/ssi/aspeed_smc: Fix incorrect FMC_WDT2 register read on AST1030

On AST1030, reading the FMC_WDT2 register always returns 0xFFFFFFFF.
This issue is due to the aspeed_smc_read function, which checks for the
ASPEED_SMC_FEATURE_WDT_CONTROL feature. Since AST1030 was missing this
feature flag, the read operation fails and returns -1.

To resolve this, add the WDT_CONTROL feature to AST1030's feature set
so that FMC_WDT2 can be correctly accessed by firmware.

Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Fixes: 2850df6a81bcdc2e063dfdd56751ee2d11c58030 ("aspeed/smc: Add AST1030 support ")
Link: https://lore.kernel.org/qemu-devel/20250804014633.512737-1-jamin_lin@aspeedtech.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>