mb/google/bluey: Update SPI flash vendor selection

This commit refactors the SPI flash vendor selection for Google Bluey
boards to accurately reflect the components used by each variant.

Previously, `SPI_FLASH_WINBOND` was unconditionally selected for
`BOARD_GOOGLE_BLUEY_COMMON`. This is incorrect as different Bluey
variants may use different SPI flash chips.

This change now specifically selects:
- `SPI_FLASH_MACRONIX` for `BOARD_GOOGLE_BLUEY`
- `SPI_FLASH_WINBOND` for `BOARD_GOOGLE_QUENBI`

This ensures that the correct SPI flash driver is enabled for each
specific board variant, as per underlying hardware design.

TEST=Able to build google/bluey.

Change-Id: I7deaed90a7f6533ed4fe9fd815715dabdaa561a3
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88267
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Dinesh Gehlot <digehlot@google.com>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-by: Pranava Y N <pranavayn@google.com>

src/mainboard/google/bluey/Kconfig

@@ -8,7 +8,6 @@ config BOARD_GOOGLE_BLUEY_COMMON
 	select SOC_QUALCOMM_X1P42100
 	select SPI_FLASH
 	select SPI_FLASH_FORCE_4_BYTE_ADDR_MODE
-	select SPI_FLASH_WINBOND
 
 config BOARD_GOOGLE_BASEBOARD_BLUEY
 	def_bool n
@@ -18,12 +17,14 @@ config BOARD_GOOGLE_BLUEY
 	select BOARD_GOOGLE_BASEBOARD_BLUEY
 	select MAINBOARD_HAS_FINGERPRINT_VIA_USB
 	select MISSING_BOARD_RESET
+	select SPI_FLASH_MACRONIX
 
 config BOARD_GOOGLE_QUENBI
 	select BOARD_GOOGLE_BASEBOARD_BLUEY
 	select MAINBOARD_HAS_CHROME_EC
 	select MAINBOARD_HAS_FINGERPRINT_VIA_SPI
 	select MAINBOARD_HAS_GOOGLE_TPM
+	select SPI_FLASH_WINBOND
 
 if BOARD_GOOGLE_BLUEY_COMMON