firmware: google: Properly state IOMEM dependency

The Google Coreboot implementation requires IOMEM functions
(memmremap, memunmap, devm_memremap), but does not specify this is its
Kconfig. This results in build errors when HAS_IOMEM is not set, such as
on some UML configurations:

/usr/bin/ld: drivers/firmware/google/coreboot_table.o: in function `coreboot_table_probe':
coreboot_table.c:(.text+0x311): undefined reference to `memremap'
/usr/bin/ld: coreboot_table.c:(.text+0x34e): undefined reference to `memunmap'
/usr/bin/ld: drivers/firmware/google/memconsole-coreboot.o: in function `memconsole_probe':
memconsole-coreboot.c:(.text+0x12d): undefined reference to `memremap'
/usr/bin/ld: memconsole-coreboot.c:(.text+0x17e): undefined reference to `devm_memremap'
/usr/bin/ld: memconsole-coreboot.c:(.text+0x191): undefined reference to `memunmap'
/usr/bin/ld: drivers/firmware/google/vpd.o: in function `vpd_section_destroy.isra.0':
vpd.c:(.text+0x300): undefined reference to `memunmap'
/usr/bin/ld: drivers/firmware/google/vpd.o: in function `vpd_section_init':
vpd.c:(.text+0x382): undefined reference to `memremap'
/usr/bin/ld: vpd.c:(.text+0x459): undefined reference to `memunmap'
/usr/bin/ld: drivers/firmware/google/vpd.o: in function `vpd_probe':
vpd.c:(.text+0x59d): undefined reference to `memremap'
/usr/bin/ld: vpd.c:(.text+0x5d3): undefined reference to `memunmap'
collect2: error: ld returned 1 exit status

Fixes: a28aad66da ("firmware: coreboot: Collapse platform drivers into bus core")
Acked-By: anton ivanov <anton.ivanov@cambridgegreys.com>
Acked-By: Julius Werner <jwerner@chromium.org>
Signed-off-by: David Gow <davidgow@google.com>
Link: https://lore.kernel.org/r/20220225041502.1901806-1-davidgow@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/firmware/google/Kconfig

@@ -21,7 +21,7 @@ config GOOGLE_SMI
 
 config GOOGLE_COREBOOT_TABLE
 	tristate "Coreboot Table Access"
-	depends on ACPI || OF
+	depends on HAS_IOMEM && (ACPI || OF)
 	help
 	  This option enables the coreboot_table module, which provides other
 	  firmware modules access to the coreboot table. The coreboot table