mb/google/guybrush: Remove unused sleep GPIO table

On Guybrush, there wasn't a need for a sleep GPIO table.
Remove the TODO and filler table and function to reduce
unnecessary function calls/overhead.  Missed changes
to variant.h in initial commit(already merged)

BUG=b:232952508
TEST=Builds

Signed-off-by: Jon Murphy <jpmurphy@google.com>
Change-Id: Idba1a9eeea5ea5f5922281668ec17c4f065a654d
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64643
Reviewed-by: Rob Barnes <robbarnes@google.com>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/guybrush/variants/baseboard/include/baseboard/variants.h

@@ -37,9 +37,6 @@ const struct soc_amd_gpio *variant_bootblock_gpio_table(size_t *size);
 /* This function provides GPIO settings before PCIe enumeration. */
 const struct soc_amd_gpio *variant_pcie_gpio_table(size_t *size);
 
-/* This function provides GPIO settings before entering sleep. */
-const struct soc_amd_gpio *variant_sleep_gpio_table(size_t *size);
-
 /* This function provides GPIO settings for eSPI bus. */
 const struct soc_amd_gpio *variant_espi_gpio_table(size_t *size);