[xen staging] Update Xen version to 4.21.0-rc2

[patchbot@xxxxxxx]

commit eff32008be0d2718d32d60245650ff6f88fb3d13
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Wed Oct 22 12:01:02 2025 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Wed Oct 22 12:01:02 2025 +0100

    Update Xen version to 4.21.0-rc2
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/Makefile b/xen/Makefile
index ba8c7147a2..a0bd29fe11 100644
--- a/xen/Makefile
+++ b/xen/Makefile
@@ -6,7 +6,7 @@ this-makefile := $(call lastword,$(MAKEFILE_LIST))
 # All other places this is stored (eg. compile.h) should be autogenerated.
 export XEN_VERSION       = 4
 export XEN_SUBVERSION    = 21
-export XEN_EXTRAVERSION ?= .0-rc1$(XEN_VENDORVERSION)
+export XEN_EXTRAVERSION ?= .0-rc2$(XEN_VENDORVERSION)
 export XEN_FULLVERSION   = $(XEN_VERSION).$(XEN_SUBVERSION)$(XEN_EXTRAVERSION)
 -include xen-version
 
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generated by git-patchbot for /home/xen/git/xen.git#staging