swupdate: Fix trailing slashes

This fixes warnings [1] about trailing slashes on ${S} and ${B}.

[1] - https://github.com/openembedded/openembedded-core/commit/8a4c473c07cba159cf88ed775b9f073c6adf31d4

Signed-off-by: Justin Standring <me@justinstandring.com>

recipes-support/swupdate/swupdate.inc

@@ -77,8 +77,8 @@ RDEPENDS_${PN}-tools += "${PN}-client ${PN}-progress ${PN}-tools-hawkbit \
     ${@bb.utils.contains('DISTRO_FEATURES','systemd','${PN}-usb','',d)} \
 "
 
-S = "${WORKDIR}/git/"
-B = "${WORKDIR}/build/"
+S = "${WORKDIR}/git"
+B = "${WORKDIR}/build"
 
 EXTRA_OEMAKE += " O=${B} HOSTCC="${BUILD_CC}" HOSTCXX="${BUILD_CXX}" LD="${CC}" DESTDIR="${D}" LIBDIR="${libdir}" V=1 ARCH=${TARGET_ARCH} CROSS_COMPILE=${TARGET_PREFIX} SKIP_STRIP=y"