bdk: mc: reduce ahb aperture by 4KB

The state machine automatically uses TOM + 4KB as real top address.
This can cause issues with HW that accesses that low RAM range,
since once the request enters ARC can't be redirected to MC and can hang.

bdk/mem/mc.c

@@ -113,7 +113,7 @@ void mc_enable_ahb_redirect()
 	CLOCK(CLK_RST_CONTROLLER_LVL2_CLK_GATE_OVRD) |= BIT(19);
 	//MC(MC_IRAM_REG_CTRL) &= ~BIT(0);
 	MC(MC_IRAM_BOM) = IRAM_BASE;
-	MC(MC_IRAM_TOM) = DRAM_START; // Default is only IRAM: 0x4003F000.
+	MC(MC_IRAM_TOM) = DRAM_START - 1; // Default is only IRAM: 0x4003F000.
 }
 
 void mc_disable_ahb_redirect()