uwe5622: fix -Wmissing-prototypes warnings (155 -> 2)

Add 'static' to file-private functions and cross-file forward
declarations to type-aware area headers. No functional change.

Verified building into kernel 6.18 (odroidm1): 0 errors, warnings 155 -> 2.
The two residuals are intentional: do_gettimeofday (driver redefines the
kernel-removed API, #defined elsewhere) and sleep_test_thread (a kthread
with an intentional infinite loop, where 'static' trips -Werror=return-type).

Assisted-by: Claude:claude-opus-4.8

Author: iav

lib/functions/compilation/patch/drivers_network.sh

@@ -636,6 +636,8 @@ driver_uwe5622() {
 		if linux-version compare "${version}" ge 7.1; then
 			process_patch_file "${SRC}/patch/misc/wireless-uwe5622/uwe5622-v7.1.patch" "applying"
 		fi
+
+		process_patch_file "${SRC}/patch/misc/wireless-uwe5622/wireless-uwe5622-Fix-missing-prototypes.patch" "applying"
 	fi
 }