intel/apollolake: Add helper routine for spi reg read

BUG=chrome-os-partner:54563

Change-Id: I56bc6b5292aec676103a436048abee8577edd961
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/15268
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/intel/apollolake/include/soc/spi.h

@@ -75,4 +75,6 @@
  */
 int spi_read_status(uint8_t *status);
 
+/* Read SPI controller register. */
+uint32_t spi_ctrlr_reg_read(uint16_t reg);
 #endif

src/soc/intel/apollolake/spi.c

@@ -70,6 +70,12 @@ static uint32_t _spi_ctrlr_reg_read(struct spi_ctx *ctx, uint16_t reg)
 	return read32((void *)addr);
 }
 
+uint32_t spi_ctrlr_reg_read(uint16_t reg)
+{
+	BOILERPLATE_CREATE_CTX(ctx);
+	return _spi_ctrlr_reg_read(ctx, reg);
+}
+
 /* Write to register in the SPI controller. 'reg' is the register offset. */
 static void _spi_ctrlr_reg_write(struct spi_ctx *ctx, uint16_t reg,
 				 uint32_t val)