Fix typos in the STM32 DAC header file. From Petteri Aimonen

arch/arm/src/stm32/chip/stm32_dac.h

@@ -55,7 +55,7 @@
 #define STM32_DAC_DHR12L1_OFFSET  0x000c /* DAC channel1 12-bit left aligned data holding register */
 #define STM32_DAC_DHR8R1_OFFSET   0x0010 /* DAC channel1 8-bit right aligned data holding register */
 #define STM32_DAC_DHR12R2_OFFSET  0x0014 /* DAC channel2 12-bit right aligned data holding register */
-#define STM32_DAC_DHR12L_OFFSET   0x0018 /* DAC channel2 12-bit left aligned data holding register */
+#define STM32_DAC_DHR12L2_OFFSET  0x0018 /* DAC channel2 12-bit left aligned data holding register */
 #define STM32_DAC_DHR8R2_OFFSET   0x001c /* DAC channel2 8-bit right-aligned data holding register */
 #define STM32_DAC_DHR12RD_OFFSET  0x0020 /* Dual DAC 12-bit right-aligned data holding register */
 #define STM32_DAC_DHR12LD_OFFSET  0x0024 /* DUAL DAC 12-bit left aligned data holding register */
@@ -72,7 +72,7 @@
 #define STM32_DAC_DHR12L1         (STM32_DAC_BASE+STM32_DAC_DHR12L1_OFFSET)
 #define STM32_DAC_DHR8R1          (STM32_DAC_BASE+STM32_DAC_DHR8R1_OFFSET)
 #define STM32_DAC_DHR12R2         (STM32_DAC_BASE+STM32_DAC_DHR12R2_OFFSET)
-#define STM32_DAC_DHR12L          (STM32_DAC_BASE+STM32_DAC_DHR12L_OFFSET)
+#define STM32_DAC_DHR12L2         (STM32_DAC_BASE+STM32_DAC_DHR12L2_OFFSET)
 #define STM32_DAC_DHR8R2          (STM32_DAC_BASE+STM32_DAC_DHR8R2_OFFSET)
 #define STM32_DAC_DHR12RD         (STM32_DAC_BASE+STM32_DAC_DHR12RD_OFFSET)
 #define STM32_DAC_DHR12LD         (STM32_DAC_BASE+STM32_DAC_DHR12LD_OFFSET)