src/platform/kgpe/default.nix: set USE_OPTION_TABLE=no

Upstream describes this option as "Enable this option if coreboot
shall read options from the CMOS NVRAM instead of using hard-coded
values."

The RTC_BOOT_BYTE (which controls normal/fallback) indicator is
always taken from CMOS NVRAM, regardless of how this option is set.
When set to `no`, no other parts of the CMOS NVRAM are read or
written.

On KGPE-D16 I have found that USE_OPTION_TABLE=yes is frustratingly
flaky and unstable; about 1 in 20 boots will hang in the PNP device
enumeration.  Apparently during SMP boot, multiple cores attempt to
access the (single) CMOS NVRAM concurrently, causing massive
headaches.  Please don't turn this option on unless you are willing
to deal with extreme frustration.

src/platform/kgpe/default.nix

@@ -50,9 +50,24 @@
       config = with lib.kernel; {
         CBFS_PREFIX = lib.mkForce (freeform "prefix");
 
-        # (freeform "Enable this option if coreboot shall read options from the "CMOS"
-        # NVRAM instead of using hard-coded values."
-        USE_OPTION_TABLE = lib.mkForce yes;
+        # Upstream describes this option as "Enable this option if
+        # coreboot shall read options from the CMOS NVRAM instead of
+        # using hard-coded values."
+        #
+        # The RTC_BOOT_BYTE (which controls normal/fallback)
+        # indicator is always taken from CMOS NVRAM, regardless of
+        # how this option is set.  When set to `no`, no other parts
+        # of the CMOS NVRAM are read or written.
+        #
+        # On KGPE-D16 I have found that USE_OPTION_TABLE=yes is
+        # frustratingly flaky and unstable; about 1 in 20 boots will
+        # hang in the PNP device enumeration.  Apparently during SMP
+        # boot, multiple cores attempt to access the (single) CMOS
+        # NVRAM concurrently, causing massive headaches.  Please
+        # don't turn this option on unless you are willing to deal
+        # with extreme frustration.
+        #
+        USE_OPTION_TABLE = lib.mkForce no;
 
         BOARD_ASUS_KGPE_D16 = lib.mkForce yes;
         VENDOR_ASUS = lib.mkForce yes;