lc823450 spi flash * arch/arm/src/lc823450: Add SPI flash driver for lc823450 NOTE: Only bus accelerator mode is supported. Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com> * arch/arm/src/lc823450: Remove unnecessary settings in Kconfig Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com> Approved-by: GregoryN <gnutt@nuttx.org>