kernel: Remove patch for kernel 5.15

This patch was accidentally backported from master for kernel 5.15 too.
Remove the version for kernel 5.15 and keep the version for kernel 5.10.

Fixes: 9ab337dfbc ("kernel: backport pgalloc memory leak fix")
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

target/linux/generic/backport-5.15/350-v5.18-MIPS-pgalloc-fix-memory-leak-caused-by-pgd_free.patch

@@ -1,48 +0,0 @@
-From 7f297c70bebd20f3e02c9b6046e4e5e71d38ffe9 Mon Sep 17 00:00:00 2001
-From: Yaliang Wang <Yaliang.Wang@windriver.com>
-Date: Thu, 10 Mar 2022 19:31:16 +0800
-Subject: [PATCH] MIPS: pgalloc: fix memory leak caused by pgd_free()
-
-pgd page is freed by generic implementation pgd_free() since commit
-f9cb654cb550 ("asm-generic: pgalloc: provide generic pgd_free()"),
-however, there are scenarios that the system uses more than one page as
-the pgd table, in such cases the generic implementation pgd_free() won't
-be applicable anymore. For example, when PAGE_SIZE_4KB is enabled and
-MIPS_VA_BITS_48 is not enabled in a 64bit system, the macro "PGD_ORDER"
-will be set as "1", which will cause allocating two pages as the pgd
-table. Well, at the same time, the generic implementation pgd_free()
-just free one pgd page, which will result in the memory leak.
-
-The memory leak can be easily detected by executing shell command:
-"while true; do ls > /dev/null; grep MemFree /proc/meminfo; done"
-
-Fixes: f9cb654cb550 ("asm-generic: pgalloc: provide generic pgd_free()")
-Signed-off-by: Yaliang Wang <Yaliang.Wang@windriver.com>
-Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
-(cherry picked from commit 2bc5bab9a763d520937e4f3fe8df51c6a1eceb97)
----
- arch/mips/include/asm/pgalloc.h | 6 ++++++
- 1 file changed, 6 insertions(+)
-
---- a/arch/mips/include/asm/pgalloc.h
-+++ b/arch/mips/include/asm/pgalloc.h
-@@ -15,6 +15,7 @@
- 
- #define __HAVE_ARCH_PMD_ALLOC_ONE
- #define __HAVE_ARCH_PUD_ALLOC_ONE
-+#define __HAVE_ARCH_PGD_FREE
- #include <asm-generic/pgalloc.h>
- 
- static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
-@@ -48,6 +49,11 @@ static inline void pud_populate(struct m
- extern void pgd_init(unsigned long page);
- extern pgd_t *pgd_alloc(struct mm_struct *mm);
- 
-+static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
-+{
-+	free_pages((unsigned long)pgd, PGD_ORDER);
-+}
-+
- #define __pte_free_tlb(tlb,pte,address)			\
- do {							\
- 	pgtable_pte_page_dtor(pte);			\