powerpc/prom_init: Fix shellcheck warnings

Fix "Double quote to prevent globbing and word splitting."
warning from shellcheck

Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Reviewed-by: Stephen Rothwell <sfr@cab.auug.org.au>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250518044107.39928-3-maddy@linux.ibm.com

Author: maddy-kerneldev

arch/powerpc/kernel/prom_init_check.sh

@@ -15,8 +15,8 @@
 
 has_renamed_memintrinsics()
 {
-	grep -q "^CONFIG_KASAN=y$" ${KCONFIG_CONFIG} && \
-		! grep -q "^CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX=y" ${KCONFIG_CONFIG}
+	grep -q "^CONFIG_KASAN=y$" "${KCONFIG_CONFIG}" && \
+		! grep -q "^CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX=y" "${KCONFIG_CONFIG}"
 }
 
 if has_renamed_memintrinsics
@@ -42,15 +42,15 @@ check_section()
 {
     file=$1
     section=$2
-    size=$(objdump -h -j $section $file 2>/dev/null | awk "\$2 == \"$section\" {print \$3}")
+    size=$(objdump -h -j "$section" "$file" 2>/dev/null | awk "\$2 == \"$section\" {print \$3}")
     size=${size:-0}
-    if [ $size -ne 0 ]; then
+    if [ "$size" -ne 0 ]; then
 	ERROR=1
 	echo "Error: Section $section not empty in prom_init.c" >&2
     fi
 }
 
-for UNDEF in $($NM -u $OBJ | awk '{print $2}')
+for UNDEF in $($NM -u "$OBJ" | awk '{print $2}')
 do
 	# On 64-bit nm gives us the function descriptors, which have
 	# a leading . on the name, so strip it off here.
@@ -87,8 +87,8 @@ do
 	fi
 done
 
-check_section $OBJ .data
-check_section $OBJ .bss
-check_section $OBJ .init.data
+check_section "$OBJ" .data
+check_section "$OBJ" .bss
+check_section "$OBJ" .init.data
 
 exit $ERROR