Update to android-mainline kernel headers v5.4.

Update generate_uapi_headers.sh to checkout the android mainline
kernel. Also, add a small modification to look for the kernel directory
in common not linux-stable.

Remove deprecated android headers from android/uapi/linux. Also,
remove f_accessory.h since it's in the android mainline kernel.

Test: Builds and runs on walleye.
Change-Id: Ia371305e19f56e6bcc2db6d5b4d299819f07ffc6
diff --git a/libc/kernel/uapi/linux/mdio.h b/libc/kernel/uapi/linux/mdio.h
index 14f1e77..3bbe433 100644
--- a/libc/kernel/uapi/linux/mdio.h
+++ b/libc/kernel/uapi/linux/mdio.h
@@ -47,11 +47,14 @@
 #define MDIO_AN_ADVERTISE 16
 #define MDIO_AN_LPA 19
 #define MDIO_PCS_EEE_ABLE 20
+#define MDIO_PCS_EEE_ABLE2 21
 #define MDIO_PMA_NG_EXTABLE 21
 #define MDIO_PCS_EEE_WK_ERR 22
 #define MDIO_PHYXS_LNSTAT 24
 #define MDIO_AN_EEE_ADV 60
 #define MDIO_AN_EEE_LPABLE 61
+#define MDIO_AN_EEE_ADV2 62
+#define MDIO_AN_EEE_LPABLE2 63
 #define MDIO_PMA_10GBT_SWAPPOL 130
 #define MDIO_PMA_10GBT_TXPWR 131
 #define MDIO_PMA_10GBT_SNR 133
@@ -217,6 +220,12 @@
 #define MDIO_EEE_1000KX 0x0010
 #define MDIO_EEE_10GKX4 0x0020
 #define MDIO_EEE_10GKR 0x0040
+#define MDIO_EEE_40GR_FW 0x0100
+#define MDIO_EEE_40GR_DS 0x0200
+#define MDIO_EEE_100GR_FW 0x1000
+#define MDIO_EEE_100GR_DS 0x2000
+#define MDIO_EEE_2_5GT 0x0001
+#define MDIO_EEE_5GT 0x0002
 #define MDIO_PMA_NG_EXTABLE_2_5GBT 0x0001
 #define MDIO_PMA_NG_EXTABLE_5GBT 0x0002
 #define MDIO_PMA_LASI_RX_PHYXSLFLT 0x0001