misra: update list of GCC extensions used by Xen

__inline and __inline__ are already handled by ECLAIR but
C-language-toolchain.rst doesn't reflect that. Update the doc.

No functional change.

Signed-off-by: Nicola Vetrini <nicola.vetrini@bugseng.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

docs/misra/C-language-toolchain.rst

@@ -86,6 +86,8 @@ The table columns are as follows:
           see Sections "6.48 Alternate Keywords" and "6.47.2.1 Volatile" of GCC_MANUAL.
        __const__:
           see Section "6.48 Alternate Keywords" of GCC_MANUAL.
+       __inline, __inline__:
+          see Section "6.48 Alternate Keywords" of GCC_MANUAL.
        typeof, __typeof__:
           see Section "6.7 Referring to a Type with typeof" of GCC_MANUAL.
        __alignof__, __alignof: