[efi] Fix .rel.data.* being erroneously merged into .data on ARM

Fix section pattern code to exclude .rel.data.* sections from being
merged into .data. Otherwise relocations in those sections are lost
in final binary

Reviewed by:	andrew
MFC after:	3 days
Differential Revision:	https://reviews.freebsd.org/D9108

sys/boot/efi/loader/arch/arm/ldscript.arm

@@ -18,7 +18,7 @@ SECTIONS
   . = ALIGN(16);
   .data    :
   {
-    *(.data *.data.*)
+    *(.data .data.*)
     *(.gnu.linkonce.d*)
     *(.rodata)
     *(.rodata.*)