Improvements for H7 towards the DMA support
arch/arm/include/stm32h7/stm32h7x3xx_irq.h: fix typos and rename DMA1/2 irq names to match those from other STM32
arch/arm/src/stm32h7/chip/stm32_bdma.h: add auxiliary definitions
arch/arm/src/stm32h7/chip/stm32_dma.h: cosmetic changes
arch/arm/src/stm32h7/chip/stm32_dmamux.h: add auxliary definitions and fix some typos
arch/arm/src/stm32h7/chip/stm32_mdma.h: add auxliary definitions and fix some typos
arch/arm/src/stm32h7/chip/stm32h7x3xx_dmamux.h: add DMAMAP definitions for MDMA, DMA1, DMA2 and BDMA
arch/arm/src/stm32h7/chip/stm32h7x3xx_memorymap.h: fix AHB1 base adresses and add some address blocks
arch/arm/src/stm32h7/chip/stm32h7x3xx_rcc.h: fix some definitions to match other STM32 ports
arch/arm/src/stm32h7/stm32_allocateheap.c: use SRAM from D2 domain (SRAM123) for now
arch/arm/src/stm32h7/stm32h7x3xx_rcc.c: enable clock for MDMA and BDMA
Approved-by: Gregory Nutt <gnutt@nuttx.org>