vgabios: Fix broken build resulting from e5749978.

The e5749978 commit added -fno-merge-constants to the compile flag.
That option changes the names of ".rodata" sections.  Update
vgalayout.lds.S so that the vgabios can continue to build.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
diff --git a/vgasrc/vgalayout.lds.S b/vgasrc/vgalayout.lds.S
index 08a5f32..533734d 100644
--- a/vgasrc/vgalayout.lds.S
+++ b/vgasrc/vgalayout.lds.S
@@ -13,8 +13,7 @@
                 KEEP(*(.rom.header))
                 *(.text.*)
                 _rodata = . ;
-                *(.rodata.__func__.*)
-                *(.rodata.str1.1)
+                *(.rodata*)
                 *(.data16.*)
                 }