ARM: dts: msm: Add SPI config regs base address for all targets

Add base address of shared SPI config registers for all targets
and provided name as "spi_cfg_regs".

Change-Id: I0138f9367a6619a4a3e3af39a6a7f6deee0637c4
Signed-off-by: Raghavendra Kakarla <rkakarla@codeaurora.org>